diff --git a/common_features.mk b/common_features.mk
index 8b5ee071d7..6193597174 100644
--- a/common_features.mk
+++ b/common_features.mk
@@ -183,7 +183,7 @@ else
         SRC += $(PLATFORM_COMMON_DIR)/eeprom_stm32.c
         SRC += $(PLATFORM_COMMON_DIR)/flash_stm32.c
         OPT_DEFS += -DEEPROM_EMU_STM32F072xB
-      else ifneq ($(filter $(MCU_SERIES)_$(MCU_LDSCRIPT),STM32F4xx_STM32F401xC STM32F4xx_STM32F411xE),)
+      else ifneq ($(filter $(MCU_SERIES)_$(MCU_LDSCRIPT),STM32F4xx_STM32F401xC STM32F4xx_STM32F411xE STM32F4xx_STM32F405xG),)
         OPT_DEFS += -DEEPROM_DRIVER
         COMMON_VPATH += $(DRIVER_PATH)/eeprom
         SRC += eeprom_driver.c
diff --git a/data/schemas/keyboard.jsonschema b/data/schemas/keyboard.jsonschema
index 15f407fce4..27507c78a3 100644
--- a/data/schemas/keyboard.jsonschema
+++ b/data/schemas/keyboard.jsonschema
@@ -13,7 +13,7 @@
         },
         "processor": {
             "type": "string",
-            "enum": ["cortex-m0", "cortex-m0plus", "cortex-m3", "cortex-m4", "MKL26Z64", "MK20DX128", "MK20DX256", "MK66F18", "STM32F042", "STM32F072", "STM32F103", "STM32F303", "STM32F401", "STM32F407", "STM32F411", "STM32F446", "STM32G431", "STM32G474", "STM32L412", "STM32L422", "STM32L433", "STM32L443", "atmega16u2", "atmega32u2", "atmega16u4", "atmega32u4", "at90usb162", "at90usb646", "at90usb647", "at90usb1286", "at90usb1287", "atmega32a", "atmega328p", "atmega328", "attiny85", "unknown"]
+            "enum": ["cortex-m0", "cortex-m0plus", "cortex-m3", "cortex-m4", "MKL26Z64", "MK20DX128", "MK20DX256", "MK66F18", "STM32F042", "STM32F072", "STM32F103", "STM32F303", "STM32F401", "STM32F405", "STM32F407", "STM32F411", "STM32F446", "STM32G431", "STM32G474", "STM32L412", "STM32L422", "STM32L433", "STM32L443", "atmega16u2", "atmega32u2", "atmega16u4", "atmega32u4", "at90usb162", "at90usb646", "at90usb647", "at90usb1286", "at90usb1287", "atmega32a", "atmega328p", "atmega328", "attiny85", "unknown"]
         },
         "audio": {
             "type": "object",
diff --git a/docs/compatible_microcontrollers.md b/docs/compatible_microcontrollers.md
index 2bf3b0ebb7..0ad5d48214 100644
--- a/docs/compatible_microcontrollers.md
+++ b/docs/compatible_microcontrollers.md
@@ -27,6 +27,7 @@ You can also use any ARM chip with USB that [ChibiOS](https://www.chibios.org) s
  * [STM32F103](https://www.st.com/en/microcontrollers-microprocessors/stm32f103.html)
  * [STM32F303](https://www.st.com/en/microcontrollers-microprocessors/stm32f303.html)
  * [STM32F401](https://www.st.com/en/microcontrollers-microprocessors/stm32f401.html)
+ * [STM32F405](https://www.st.com/en/microcontrollers-microprocessors/stm32f405-415.html)
  * [STM32F407](https://www.st.com/en/microcontrollers-microprocessors/stm32f407-417.html)
  * [STM32F411](https://www.st.com/en/microcontrollers-microprocessors/stm32f411.html)
  * [STM32F446](https://www.st.com/en/microcontrollers-microprocessors/stm32f446.html)
diff --git a/docs/ja/compatible_microcontrollers.md b/docs/ja/compatible_microcontrollers.md
index 7a3484fa8c..23f32bbb60 100644
--- a/docs/ja/compatible_microcontrollers.md
+++ b/docs/ja/compatible_microcontrollers.md
@@ -32,6 +32,7 @@ QMK は十分な容量のフラッシュメモリを備えた USB 対応 AVR ま
 * [STM32F103](https://www.st.com/en/microcontrollers-microprocessors/stm32f103.html)
 * [STM32F303](https://www.st.com/en/microcontrollers-microprocessors/stm32f303.html)
 * [STM32F401](https://www.st.com/en/microcontrollers-microprocessors/stm32f401.html)
+* [STM32F405](https://www.st.com/en/microcontrollers-microprocessors/stm32f405-415.html)
 * [STM32F407](https://www.st.com/en/microcontrollers-microprocessors/stm32f407-417.html)
 * [STM32F411](https://www.st.com/en/microcontrollers-microprocessors/stm32f411.html)
 * [STM32F446](https://www.st.com/en/microcontrollers-microprocessors/stm32f446.html)
diff --git a/keyboards/handwired/onekey/stm32f405_feather/config.h b/keyboards/handwired/onekey/stm32f405_feather/config.h
new file mode 100644
index 0000000000..32d7807975
--- /dev/null
+++ b/keyboards/handwired/onekey/stm32f405_feather/config.h
@@ -0,0 +1,25 @@
+/* Copyright 2019
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+#include "config_common.h"
+
+#define PRODUCT Onekey Adafruit Feather STM32F405
+
+#define MATRIX_COL_PINS { C2 }
+#define MATRIX_ROW_PINS { C3 }
+#define UNUSED_PINS
diff --git a/keyboards/handwired/onekey/stm32f405_feather/readme.md b/keyboards/handwired/onekey/stm32f405_feather/readme.md
new file mode 100644
index 0000000000..49a05725d5
--- /dev/null
+++ b/keyboards/handwired/onekey/stm32f405_feather/readme.md
@@ -0,0 +1,7 @@
+# Adafruit Feather STM32F405 Express onekey
+
+* Supported Hardware: [Adafruit Feather STM32F405 Express](https://www.adafruit.com/product/4382)
+
+To trigger keypress, short together pins *GPIO 12 / PC2* and *GPIO 11 / PC3*.
+
+https://learn.adafruit.com/adafruit-stm32f405-feather-express/dfu-bootloader-details#enabling-dfu-bootloader-mode-3045622-2
\ No newline at end of file
diff --git a/keyboards/handwired/onekey/stm32f405_feather/rules.mk b/keyboards/handwired/onekey/stm32f405_feather/rules.mk
new file mode 100644
index 0000000000..bff7a7e297
--- /dev/null
+++ b/keyboards/handwired/onekey/stm32f405_feather/rules.mk
@@ -0,0 +1,8 @@
+# MCU name
+MCU = STM32F405
+
+# Bootloader selection
+BOOTLOADER = stm32-dfu
+
+# Enter lower-power sleep mode when on the ChibiOS idle thread
+OPT_DEFS += -DCORTEX_ENABLE_WFI_IDLE=TRUE
diff --git a/platforms/chibios/boards/GENERIC_STM32_F405XG/board/board.mk b/platforms/chibios/boards/GENERIC_STM32_F405XG/board/board.mk
new file mode 100644
index 0000000000..6c837bb8ee
--- /dev/null
+++ b/platforms/chibios/boards/GENERIC_STM32_F405XG/board/board.mk
@@ -0,0 +1,9 @@
+# List of all the board related files.
+BOARDSRC = $(CHIBIOS)/os/hal/boards/ST_STM32F4_DISCOVERY/board.c
+
+# Required include directories
+BOARDINC = $(CHIBIOS)/os/hal/boards/ST_STM32F4_DISCOVERY
+
+# Shared variables
+ALLCSRC += $(BOARDSRC)
+ALLINC  += $(BOARDINC)
\ No newline at end of file
diff --git a/platforms/chibios/boards/GENERIC_STM32_F405XG/configs/board.h b/platforms/chibios/boards/GENERIC_STM32_F405XG/configs/board.h
new file mode 100644
index 0000000000..8cb771bc12
--- /dev/null
+++ b/platforms/chibios/boards/GENERIC_STM32_F405XG/configs/board.h
@@ -0,0 +1,28 @@
+/* Copyright 2020 Nick Brassel (tzarc)
+ *
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+#pragma once
+
+#define STM32_HSECLK 12000000
+// The following is required to disable the pull-down on PA9, when PA9 is used for the keyboard matrix:
+#define BOARD_OTG_NOVBUSSENS
+
+#include_next "board.h"
+
+#undef STM32_HSE_BYPASS
+
+#undef STM32F407xx
+#define STM32F405xG
+#define STM32F405xx
diff --git a/platforms/chibios/boards/GENERIC_STM32_F405XG/configs/config.h b/platforms/chibios/boards/GENERIC_STM32_F405XG/configs/config.h
new file mode 100644
index 0000000000..cc52a953ed
--- /dev/null
+++ b/platforms/chibios/boards/GENERIC_STM32_F405XG/configs/config.h
@@ -0,0 +1,23 @@
+/* Copyright 2021 Andrei Purdea
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+/* Address for jumping to bootloader on STM32 chips. */
+/* It is chip dependent, the correct number can be looked up by checking against ST's application note AN2606.
+ */
+#define STM32_BOOTLOADER_ADDRESS 0x1FFF0000
+#ifndef EARLY_INIT_PERFORM_BOOTLOADER_JUMP
+#    define EARLY_INIT_PERFORM_BOOTLOADER_JUMP TRUE
+#endif
diff --git a/platforms/chibios/boards/GENERIC_STM32_F405XG/configs/mcuconf.h b/platforms/chibios/boards/GENERIC_STM32_F405XG/configs/mcuconf.h
new file mode 100644
index 0000000000..d2ec632d9f
--- /dev/null
+++ b/platforms/chibios/boards/GENERIC_STM32_F405XG/configs/mcuconf.h
@@ -0,0 +1,355 @@
+/*
+    ChibiOS - Copyright (C) 2006..2018 Giovanni Di Sirio
+
+    Licensed under the Apache License, Version 2.0 (the "License");
+    you may not use this file except in compliance with the License.
+    You may obtain a copy of the License at
+
+        http://www.apache.org/licenses/LICENSE-2.0
+
+    Unless required by applicable law or agreed to in writing, software
+    distributed under the License is distributed on an "AS IS" BASIS,
+    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+    See the License for the specific language governing permissions and
+    limitations under the License.
+*/
+
+#ifndef MCUCONF_H
+#define MCUCONF_H
+
+/*
+ * STM32F4xx drivers configuration.
+ * The following settings override the default settings present in
+ * the various device driver implementation headers.
+ * Note that the settings for each driver only have effect if the whole
+ * driver is enabled in halconf.h.
+ *
+ * IRQ priorities:
+ * 15...0       Lowest...Highest.
+ *
+ * DMA priorities:
+ * 0...3        Lowest...Highest.
+ */
+
+#define STM32F4xx_MCUCONF
+#define STM32F405_MCUCONF
+#define STM32F415_MCUCONF
+#define STM32F407_MCUCONF
+#define STM32F417_MCUCONF
+
+/*
+ * HAL driver system settings.
+ */
+#define STM32_NO_INIT                       FALSE
+#define STM32_PVD_ENABLE                    FALSE
+#define STM32_PLS                           STM32_PLS_LEV0
+#define STM32_BKPRAM_ENABLE                 FALSE
+#define STM32_HSI_ENABLED                   TRUE
+#define STM32_LSI_ENABLED                   TRUE
+#define STM32_HSE_ENABLED                   TRUE
+#define STM32_LSE_ENABLED                   FALSE
+#define STM32_CLOCK48_REQUIRED              TRUE
+#define STM32_SW                            STM32_SW_PLL
+#define STM32_PLLSRC                        STM32_PLLSRC_HSE
+#define STM32_PLLM_VALUE                    12
+#define STM32_PLLN_VALUE                    336
+#define STM32_PLLP_VALUE                    2
+#define STM32_PLLQ_VALUE                    7
+#define STM32_HPRE                          STM32_HPRE_DIV1
+#define STM32_PPRE1                         STM32_PPRE1_DIV4
+#define STM32_PPRE2                         STM32_PPRE2_DIV2
+#define STM32_RTCSEL                        STM32_RTCSEL_LSI
+#define STM32_RTCPRE_VALUE                  8
+#define STM32_MCO1SEL                       STM32_MCO1SEL_HSI
+#define STM32_MCO1PRE                       STM32_MCO1PRE_DIV1
+#define STM32_MCO2SEL                       STM32_MCO2SEL_SYSCLK
+#define STM32_MCO2PRE                       STM32_MCO2PRE_DIV5
+#define STM32_I2SSRC                        STM32_I2SSRC_CKIN
+#define STM32_PLLI2SN_VALUE                 192
+#define STM32_PLLI2SR_VALUE                 5
+
+/*
+ * IRQ system settings.
+ */
+#define STM32_IRQ_EXTI0_PRIORITY            6
+#define STM32_IRQ_EXTI1_PRIORITY            6
+#define STM32_IRQ_EXTI2_PRIORITY            6
+#define STM32_IRQ_EXTI3_PRIORITY            6
+#define STM32_IRQ_EXTI4_PRIORITY            6
+#define STM32_IRQ_EXTI5_9_PRIORITY          6
+#define STM32_IRQ_EXTI10_15_PRIORITY        6
+#define STM32_IRQ_EXTI16_PRIORITY           6
+#define STM32_IRQ_EXTI17_PRIORITY           15
+#define STM32_IRQ_EXTI18_PRIORITY           6
+#define STM32_IRQ_EXTI19_PRIORITY           6
+#define STM32_IRQ_EXTI20_PRIORITY           6
+#define STM32_IRQ_EXTI21_PRIORITY           15
+#define STM32_IRQ_EXTI22_PRIORITY           15
+
+/*
+ * ADC driver system settings.
+ */
+#define STM32_ADC_ADCPRE                    ADC_CCR_ADCPRE_DIV4
+#define STM32_ADC_USE_ADC1                  FALSE
+#define STM32_ADC_USE_ADC2                  FALSE
+#define STM32_ADC_USE_ADC3                  FALSE
+#define STM32_ADC_ADC1_DMA_STREAM           STM32_DMA_STREAM_ID(2, 4)
+#define STM32_ADC_ADC2_DMA_STREAM           STM32_DMA_STREAM_ID(2, 2)
+#define STM32_ADC_ADC3_DMA_STREAM           STM32_DMA_STREAM_ID(2, 1)
+#define STM32_ADC_ADC1_DMA_PRIORITY         2
+#define STM32_ADC_ADC2_DMA_PRIORITY         2
+#define STM32_ADC_ADC3_DMA_PRIORITY         2
+#define STM32_ADC_IRQ_PRIORITY              6
+#define STM32_ADC_ADC1_DMA_IRQ_PRIORITY     6
+#define STM32_ADC_ADC2_DMA_IRQ_PRIORITY     6
+#define STM32_ADC_ADC3_DMA_IRQ_PRIORITY     6
+
+/*
+ * CAN driver system settings.
+ */
+#define STM32_CAN_USE_CAN1                  FALSE
+#define STM32_CAN_USE_CAN2                  FALSE
+#define STM32_CAN_CAN1_IRQ_PRIORITY         11
+#define STM32_CAN_CAN2_IRQ_PRIORITY         11
+
+/*
+ * DAC driver system settings.
+ */
+#define STM32_DAC_DUAL_MODE                 FALSE
+#define STM32_DAC_USE_DAC1_CH1              FALSE
+#define STM32_DAC_USE_DAC1_CH2              FALSE
+#define STM32_DAC_DAC1_CH1_IRQ_PRIORITY     10
+#define STM32_DAC_DAC1_CH2_IRQ_PRIORITY     10
+#define STM32_DAC_DAC1_CH1_DMA_PRIORITY     2
+#define STM32_DAC_DAC1_CH2_DMA_PRIORITY     2
+#define STM32_DAC_DAC1_CH1_DMA_STREAM       STM32_DMA_STREAM_ID(1, 5)
+#define STM32_DAC_DAC1_CH2_DMA_STREAM       STM32_DMA_STREAM_ID(1, 6)
+
+/*
+ * GPT driver system settings.
+ */
+#define STM32_GPT_USE_TIM1                  FALSE
+#define STM32_GPT_USE_TIM2                  FALSE
+#define STM32_GPT_USE_TIM3                  FALSE
+#define STM32_GPT_USE_TIM4                  FALSE
+#define STM32_GPT_USE_TIM5                  FALSE
+#define STM32_GPT_USE_TIM6                  FALSE
+#define STM32_GPT_USE_TIM7                  FALSE
+#define STM32_GPT_USE_TIM8                  FALSE
+#define STM32_GPT_USE_TIM9                  FALSE
+#define STM32_GPT_USE_TIM11                 FALSE
+#define STM32_GPT_USE_TIM12                 FALSE
+#define STM32_GPT_USE_TIM14                 FALSE
+#define STM32_GPT_TIM1_IRQ_PRIORITY         7
+#define STM32_GPT_TIM2_IRQ_PRIORITY         7
+#define STM32_GPT_TIM3_IRQ_PRIORITY         7
+#define STM32_GPT_TIM4_IRQ_PRIORITY         7
+#define STM32_GPT_TIM5_IRQ_PRIORITY         7
+#define STM32_GPT_TIM6_IRQ_PRIORITY         7
+#define STM32_GPT_TIM7_IRQ_PRIORITY         7
+#define STM32_GPT_TIM8_IRQ_PRIORITY         7
+#define STM32_GPT_TIM9_IRQ_PRIORITY         7
+#define STM32_GPT_TIM11_IRQ_PRIORITY        7
+#define STM32_GPT_TIM12_IRQ_PRIORITY        7
+#define STM32_GPT_TIM14_IRQ_PRIORITY        7
+
+/*
+ * I2C driver system settings.
+ */
+#define STM32_I2C_USE_I2C1                  FALSE
+#define STM32_I2C_USE_I2C2                  FALSE
+#define STM32_I2C_USE_I2C3                  FALSE
+#define STM32_I2C_BUSY_TIMEOUT              50
+#define STM32_I2C_I2C1_RX_DMA_STREAM        STM32_DMA_STREAM_ID(1, 0)
+#define STM32_I2C_I2C1_TX_DMA_STREAM        STM32_DMA_STREAM_ID(1, 6)
+#define STM32_I2C_I2C2_RX_DMA_STREAM        STM32_DMA_STREAM_ID(1, 2)
+#define STM32_I2C_I2C2_TX_DMA_STREAM        STM32_DMA_STREAM_ID(1, 7)
+#define STM32_I2C_I2C3_RX_DMA_STREAM        STM32_DMA_STREAM_ID(1, 2)
+#define STM32_I2C_I2C3_TX_DMA_STREAM        STM32_DMA_STREAM_ID(1, 4)
+#define STM32_I2C_I2C1_IRQ_PRIORITY         5
+#define STM32_I2C_I2C2_IRQ_PRIORITY         5
+#define STM32_I2C_I2C3_IRQ_PRIORITY         5
+#define STM32_I2C_I2C1_DMA_PRIORITY         3
+#define STM32_I2C_I2C2_DMA_PRIORITY         3
+#define STM32_I2C_I2C3_DMA_PRIORITY         3
+#define STM32_I2C_DMA_ERROR_HOOK(i2cp)      osalSysHalt("DMA failure")
+
+/*
+ * I2S driver system settings.
+ */
+#define STM32_I2S_USE_SPI2                  FALSE
+#define STM32_I2S_USE_SPI3                  FALSE
+#define STM32_I2S_SPI2_IRQ_PRIORITY         10
+#define STM32_I2S_SPI3_IRQ_PRIORITY         10
+#define STM32_I2S_SPI2_DMA_PRIORITY         1
+#define STM32_I2S_SPI3_DMA_PRIORITY         1
+#define STM32_I2S_SPI2_RX_DMA_STREAM        STM32_DMA_STREAM_ID(1, 3)
+#define STM32_I2S_SPI2_TX_DMA_STREAM        STM32_DMA_STREAM_ID(1, 4)
+#define STM32_I2S_SPI3_RX_DMA_STREAM        STM32_DMA_STREAM_ID(1, 0)
+#define STM32_I2S_SPI3_TX_DMA_STREAM        STM32_DMA_STREAM_ID(1, 7)
+#define STM32_I2S_DMA_ERROR_HOOK(i2sp)      osalSysHalt("DMA failure")
+
+/*
+ * ICU driver system settings.
+ */
+#define STM32_ICU_USE_TIM1                  FALSE
+#define STM32_ICU_USE_TIM2                  FALSE
+#define STM32_ICU_USE_TIM3                  FALSE
+#define STM32_ICU_USE_TIM4                  FALSE
+#define STM32_ICU_USE_TIM5                  FALSE
+#define STM32_ICU_USE_TIM8                  FALSE
+#define STM32_ICU_USE_TIM9                  FALSE
+#define STM32_ICU_TIM1_IRQ_PRIORITY         7
+#define STM32_ICU_TIM2_IRQ_PRIORITY         7
+#define STM32_ICU_TIM3_IRQ_PRIORITY         7
+#define STM32_ICU_TIM4_IRQ_PRIORITY         7
+#define STM32_ICU_TIM5_IRQ_PRIORITY         7
+#define STM32_ICU_TIM8_IRQ_PRIORITY         7
+#define STM32_ICU_TIM9_IRQ_PRIORITY         7
+
+/*
+ * MAC driver system settings.
+ */
+#define STM32_MAC_TRANSMIT_BUFFERS          2
+#define STM32_MAC_RECEIVE_BUFFERS           4
+#define STM32_MAC_BUFFERS_SIZE              1522
+#define STM32_MAC_PHY_TIMEOUT               100
+#define STM32_MAC_ETH1_CHANGE_PHY_STATE     TRUE
+#define STM32_MAC_ETH1_IRQ_PRIORITY         13
+#define STM32_MAC_IP_CHECKSUM_OFFLOAD       0
+
+/*
+ * PWM driver system settings.
+ */
+#define STM32_PWM_USE_ADVANCED              FALSE
+#define STM32_PWM_USE_TIM1                  FALSE
+#define STM32_PWM_USE_TIM2                  FALSE
+#define STM32_PWM_USE_TIM3                  FALSE
+#define STM32_PWM_USE_TIM4                  FALSE
+#define STM32_PWM_USE_TIM5                  FALSE
+#define STM32_PWM_USE_TIM8                  FALSE
+#define STM32_PWM_USE_TIM9                  FALSE
+#define STM32_PWM_TIM1_IRQ_PRIORITY         7
+#define STM32_PWM_TIM2_IRQ_PRIORITY         7
+#define STM32_PWM_TIM3_IRQ_PRIORITY         7
+#define STM32_PWM_TIM4_IRQ_PRIORITY         7
+#define STM32_PWM_TIM5_IRQ_PRIORITY         7
+#define STM32_PWM_TIM8_IRQ_PRIORITY         7
+#define STM32_PWM_TIM9_IRQ_PRIORITY         7
+
+/*
+ * RTC driver system settings.
+ */
+#define STM32_RTC_PRESA_VALUE               32
+#define STM32_RTC_PRESS_VALUE               1024
+#define STM32_RTC_CR_INIT                   0
+#define STM32_RTC_TAMPCR_INIT               0
+
+/*
+ * SDC driver system settings.
+ */
+#define STM32_SDC_SDIO_DMA_PRIORITY         3
+#define STM32_SDC_SDIO_IRQ_PRIORITY         9
+#define STM32_SDC_WRITE_TIMEOUT_MS          1000
+#define STM32_SDC_READ_TIMEOUT_MS           1000
+#define STM32_SDC_CLOCK_ACTIVATION_DELAY    10
+#define STM32_SDC_SDIO_UNALIGNED_SUPPORT    TRUE
+#define STM32_SDC_SDIO_DMA_STREAM           STM32_DMA_STREAM_ID(2, 3)
+
+/*
+ * SERIAL driver system settings.
+ */
+#define STM32_SERIAL_USE_USART1             FALSE
+#define STM32_SERIAL_USE_USART2             FALSE
+#define STM32_SERIAL_USE_USART3             FALSE
+#define STM32_SERIAL_USE_UART4              FALSE
+#define STM32_SERIAL_USE_UART5              FALSE
+#define STM32_SERIAL_USE_USART6             FALSE
+#define STM32_SERIAL_USART1_PRIORITY        12
+#define STM32_SERIAL_USART2_PRIORITY        12
+#define STM32_SERIAL_USART3_PRIORITY        12
+#define STM32_SERIAL_UART4_PRIORITY         12
+#define STM32_SERIAL_UART5_PRIORITY         12
+#define STM32_SERIAL_USART6_PRIORITY        12
+
+/*
+ * SPI driver system settings.
+ */
+#define STM32_SPI_USE_SPI1                  FALSE
+#define STM32_SPI_USE_SPI2                  FALSE
+#define STM32_SPI_USE_SPI3                  FALSE
+#define STM32_SPI_SPI1_RX_DMA_STREAM        STM32_DMA_STREAM_ID(2, 0)
+#define STM32_SPI_SPI1_TX_DMA_STREAM        STM32_DMA_STREAM_ID(2, 3)
+#define STM32_SPI_SPI2_RX_DMA_STREAM        STM32_DMA_STREAM_ID(1, 3)
+#define STM32_SPI_SPI2_TX_DMA_STREAM        STM32_DMA_STREAM_ID(1, 4)
+#define STM32_SPI_SPI3_RX_DMA_STREAM        STM32_DMA_STREAM_ID(1, 0)
+#define STM32_SPI_SPI3_TX_DMA_STREAM        STM32_DMA_STREAM_ID(1, 7)
+#define STM32_SPI_SPI1_DMA_PRIORITY         1
+#define STM32_SPI_SPI2_DMA_PRIORITY         1
+#define STM32_SPI_SPI3_DMA_PRIORITY         1
+#define STM32_SPI_SPI1_IRQ_PRIORITY         10
+#define STM32_SPI_SPI2_IRQ_PRIORITY         10
+#define STM32_SPI_SPI3_IRQ_PRIORITY         10
+#define STM32_SPI_DMA_ERROR_HOOK(spip)      osalSysHalt("DMA failure")
+
+/*
+ * ST driver system settings.
+ */
+#define STM32_ST_IRQ_PRIORITY               8
+#define STM32_ST_USE_TIMER                  2
+
+/*
+ * UART driver system settings.
+ */
+#define STM32_UART_USE_USART1               FALSE
+#define STM32_UART_USE_USART2               FALSE
+#define STM32_UART_USE_USART3               FALSE
+#define STM32_UART_USE_UART4                FALSE
+#define STM32_UART_USE_UART5                FALSE
+#define STM32_UART_USE_USART6               FALSE
+#define STM32_UART_USART1_RX_DMA_STREAM     STM32_DMA_STREAM_ID(2, 5)
+#define STM32_UART_USART1_TX_DMA_STREAM     STM32_DMA_STREAM_ID(2, 7)
+#define STM32_UART_USART2_RX_DMA_STREAM     STM32_DMA_STREAM_ID(1, 5)
+#define STM32_UART_USART2_TX_DMA_STREAM     STM32_DMA_STREAM_ID(1, 6)
+#define STM32_UART_USART3_RX_DMA_STREAM     STM32_DMA_STREAM_ID(1, 1)
+#define STM32_UART_USART3_TX_DMA_STREAM     STM32_DMA_STREAM_ID(1, 3)
+#define STM32_UART_UART4_RX_DMA_STREAM      STM32_DMA_STREAM_ID(1, 2)
+#define STM32_UART_UART4_TX_DMA_STREAM      STM32_DMA_STREAM_ID(1, 4)
+#define STM32_UART_UART5_RX_DMA_STREAM      STM32_DMA_STREAM_ID(1, 0)
+#define STM32_UART_UART5_TX_DMA_STREAM      STM32_DMA_STREAM_ID(1, 7)
+#define STM32_UART_USART6_RX_DMA_STREAM     STM32_DMA_STREAM_ID(2, 2)
+#define STM32_UART_USART6_TX_DMA_STREAM     STM32_DMA_STREAM_ID(2, 7)
+#define STM32_UART_USART1_IRQ_PRIORITY      12
+#define STM32_UART_USART2_IRQ_PRIORITY      12
+#define STM32_UART_USART3_IRQ_PRIORITY      12
+#define STM32_UART_UART4_IRQ_PRIORITY       12
+#define STM32_UART_UART5_IRQ_PRIORITY       12
+#define STM32_UART_USART6_IRQ_PRIORITY      12
+#define STM32_UART_USART1_DMA_PRIORITY      0
+#define STM32_UART_USART2_DMA_PRIORITY      0
+#define STM32_UART_USART3_DMA_PRIORITY      0
+#define STM32_UART_UART4_DMA_PRIORITY       0
+#define STM32_UART_UART5_DMA_PRIORITY       0
+#define STM32_UART_USART6_DMA_PRIORITY      0
+#define STM32_UART_DMA_ERROR_HOOK(uartp)    osalSysHalt("DMA failure")
+
+/*
+ * USB driver system settings.
+ */
+#define STM32_USB_USE_OTG1                  TRUE
+#define STM32_USB_USE_OTG2                  FALSE
+#define STM32_USB_OTG1_IRQ_PRIORITY         14
+#define STM32_USB_OTG2_IRQ_PRIORITY         14
+#define STM32_USB_OTG1_RX_FIFO_SIZE         512
+#define STM32_USB_OTG2_RX_FIFO_SIZE         1024
+#define STM32_USB_HOST_WAKEUP_DURATION      2
+
+#define STM32_USB_OTG_THREAD_PRIO           NORMALPRIO+1
+#define STM32_USB_OTG_THREAD_STACK_SIZE     128
+
+/*
+ * WDG driver system settings.
+ */
+#define STM32_WDG_USE_IWDG                  FALSE
+
+#endif /* MCUCONF_H */
diff --git a/platforms/chibios/boards/common/ld/STM32F405xG.ld b/platforms/chibios/boards/common/ld/STM32F405xG.ld
new file mode 100644
index 0000000000..b7d0baa210
--- /dev/null
+++ b/platforms/chibios/boards/common/ld/STM32F405xG.ld
@@ -0,0 +1,86 @@
+/*
+    ChibiOS - Copyright (C) 2006..2018 Giovanni Di Sirio
+
+    Licensed under the Apache License, Version 2.0 (the "License");
+    you may not use this file except in compliance with the License.
+    You may obtain a copy of the License at
+
+        http://www.apache.org/licenses/LICENSE-2.0
+
+    Unless required by applicable law or agreed to in writing, software
+    distributed under the License is distributed on an "AS IS" BASIS,
+    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+    See the License for the specific language governing permissions and
+    limitations under the License.
+*/
+
+/*
+ * STM32F405xG memory setup.
+ * Note: Use of ram1 and ram2 is mutually exclusive with use of ram0.
+ */
+MEMORY
+{
+    flash0 (rx) : org = 0x08000000, len = 16k      /* Sector 0    - Init code as ROM bootloader assumes application starts here */
+    flash1 (rx) : org = 0x08004000, len = 16k      /* Sector 1    - Emulated eeprom */
+    flash2 (rx) : org = 0x08008000, len = 1M - 32k /* Sector 2..6 - Rest of firmware */
+    flash3 (rx) : org = 0x00000000, len = 0
+    flash4 (rx) : org = 0x00000000, len = 0
+    flash5 (rx) : org = 0x00000000, len = 0
+    flash6 (rx) : org = 0x00000000, len = 0
+    flash7 (rx) : org = 0x00000000, len = 0
+    ram0   (wx) : org = 0x20000000, len = 128k      /* SRAM1 + SRAM2 */
+    ram1   (wx) : org = 0x20000000, len = 112k      /* SRAM1 */
+    ram2   (wx) : org = 0x2001C000, len = 16k       /* SRAM2 */
+    ram3   (wx) : org = 0x00000000, len = 0
+    ram4   (wx) : org = 0x10000000, len = 64k       /* CCM SRAM */
+    ram5   (wx) : org = 0x40024000, len = 4k        /* BCKP SRAM */
+    ram6   (wx) : org = 0x00000000, len = 0
+    ram7   (wx) : org = 0x00000000, len = 0
+}
+
+/* For each data/text section two region are defined, a virtual region
+   and a load region (_LMA suffix).*/
+
+/* Flash region to be used for exception vectors.*/
+REGION_ALIAS("VECTORS_FLASH", flash0);
+REGION_ALIAS("VECTORS_FLASH_LMA", flash0);
+
+/* Flash region to be used for constructors and destructors.*/
+REGION_ALIAS("XTORS_FLASH", flash2);
+REGION_ALIAS("XTORS_FLASH_LMA", flash2);
+
+/* Flash region to be used for code text.*/
+REGION_ALIAS("TEXT_FLASH", flash2);
+REGION_ALIAS("TEXT_FLASH_LMA", flash2);
+
+/* Flash region to be used for read only data.*/
+REGION_ALIAS("RODATA_FLASH", flash2);
+REGION_ALIAS("RODATA_FLASH_LMA", flash2);
+
+/* Flash region to be used for various.*/
+REGION_ALIAS("VARIOUS_FLASH", flash2);
+REGION_ALIAS("VARIOUS_FLASH_LMA", flash2);
+
+/* Flash region to be used for RAM(n) initialization data.*/
+REGION_ALIAS("RAM_INIT_FLASH_LMA", flash2);
+
+/* RAM region to be used for Main stack. This stack accommodates the processing
+   of all exceptions and interrupts.*/
+REGION_ALIAS("MAIN_STACK_RAM", ram0);
+
+/* RAM region to be used for the process stack. This is the stack used by
+   the main() function.*/
+REGION_ALIAS("PROCESS_STACK_RAM", ram0);
+
+/* RAM region to be used for data segment.*/
+REGION_ALIAS("DATA_RAM", ram0);
+REGION_ALIAS("DATA_RAM_LMA", flash2);
+
+/* RAM region to be used for BSS segment.*/
+REGION_ALIAS("BSS_RAM", ram0);
+
+/* RAM region to be used for the default heap.*/
+REGION_ALIAS("HEAP_RAM", ram0);
+
+/* Generic rules inclusion.*/
+INCLUDE rules.ld
diff --git a/quantum/mcu_selection.mk b/quantum/mcu_selection.mk
index f7eaeec8ac..48c53e4da6 100644
--- a/quantum/mcu_selection.mk
+++ b/quantum/mcu_selection.mk
@@ -273,6 +273,38 @@ ifneq ($(findstring STM32F401, $(MCU)),)
   UF2_FAMILY ?= STM32F4
 endif
 
+ifneq ($(findstring STM32F405, $(MCU)),)
+  # Cortex version
+  MCU = cortex-m4
+
+  # ARM version, CORTEX-M0/M1 are 6, CORTEX-M3/M4/M7 are 7
+  ARMV = 7
+
+  ## chip/board settings
+  # - the next two should match the directories in
+  #   <chibios>/os/hal/ports/$(MCU_FAMILY)/$(MCU_SERIES)
+  MCU_FAMILY = STM32
+  MCU_SERIES = STM32F4xx
+
+  # Linker script to use
+  # - it should exist either in <chibios>/os/common/ports/ARMCMx/compilers/GCC/ld/
+  #   or <keyboard_dir>/ld/
+  MCU_LDSCRIPT ?= STM32F405xG
+
+  # Startup code to use
+  #  - it should exist in <chibios>/os/common/startup/ARMCMx/compilers/GCC/mk/
+  MCU_STARTUP ?= stm32f4xx
+
+  # Board: it should exist either in <chibios>/os/hal/boards/,
+  # <keyboard_dir>/boards/, or drivers/boards/
+  BOARD ?= GENERIC_STM32_F405XG
+
+  USE_FPU ?= yes
+
+  # UF2 settings
+  UF2_FAMILY ?= STM32F4
+endif
+
 ifneq ($(findstring STM32F407, $(MCU)),)
   # Cortex version
   MCU = cortex-m4
diff --git a/tmk_core/common/chibios/eeprom_stm32_defs.h b/tmk_core/common/chibios/eeprom_stm32_defs.h
index 57de42c6ba..cc64cda748 100644
--- a/tmk_core/common/chibios/eeprom_stm32_defs.h
+++ b/tmk_core/common/chibios/eeprom_stm32_defs.h
@@ -32,7 +32,7 @@
 #        ifndef FEE_PAGE_COUNT
 #            define FEE_PAGE_COUNT 4  // How many pages are used
 #        endif
-#    elif defined(STM32F401xC) || defined(STM32F411xE)
+#    elif defined(STM32F401xC) || defined(STM32F405xG) || defined(STM32F411xE)
 #        ifndef FEE_PAGE_SIZE
 #            define FEE_PAGE_SIZE 0x4000  // Page size = 16KByte
 #        endif
@@ -51,12 +51,14 @@
 #        define FEE_MCU_FLASH_SIZE 256  // Size in Kb
 #    elif defined(STM32F103xE) || defined(STM32F411xE)
 #        define FEE_MCU_FLASH_SIZE 512  // Size in Kb
+#    elif defined(STM32F405xG)
+#        define FEE_MCU_FLASH_SIZE 1024  // Size in Kb
 #    endif
 #endif
 
 /* Start of the emulated eeprom */
 #if !defined(FEE_PAGE_BASE_ADDRESS)
-#    if defined(STM32F401xC) || defined(STM32F411xE)
+#    if defined(STM32F401xC) || defined(STM32F405xG) || defined(STM32F411xE)
 #        ifndef FEE_PAGE_BASE_ADDRESS
 #            define FEE_PAGE_BASE_ADDRESS 0x08004000  // bodge to force 2nd 16k page
 #        endif