diff --git a/libraries/AP_HAL_ChibiOS/hwdef/Pixhawk6C/hwdef-bl.dat b/libraries/AP_HAL_ChibiOS/hwdef/Pixhawk6C/hwdef-bl.dat
index 3894214702..4f344eb61d 100644
--- a/libraries/AP_HAL_ChibiOS/hwdef/Pixhawk6C/hwdef-bl.dat
+++ b/libraries/AP_HAL_ChibiOS/hwdef/Pixhawk6C/hwdef-bl.dat
@@ -69,3 +69,30 @@ define HAL_LED_ON 0
 
 define HAL_USE_EMPTY_STORAGE 1
 define HAL_STORAGE_SIZE 16384
+
+# support flashing from SD card:
+
+# FATFS support:
+define CH_CFG_USE_MEMCORE 1
+define CH_CFG_USE_HEAP 1
+define CH_CFG_USE_SEMAPHORES 0
+define CH_CFG_USE_MUTEXES 1
+define CH_CFG_USE_DYNAMIC 1
+define CH_CFG_USE_WAITEXIT 1
+define CH_CFG_USE_REGISTRY 1
+
+# microSD support
+PD6  SDMMC2_CK SDMMC2
+PD7  SDMMC2_CMD SDMMC2
+PB14 SDMMC2_D0 SDMMC2
+PB15 SDMMC2_D1 SDMMC2
+PB3  SDMMC2_D2 SDMMC2
+PB4  SDMMC2_D3 SDMMC2
+define FATFS_HAL_DEVICE SDCD2
+
+DMA_PRIORITY SDMMC* USART6* ADC* UART* USART* SPI* TIM*
+
+# enable FAT filesystem support (needs a microSD defined via SDMMC)
+define HAL_OS_FATFS_IO 1
+
+define AP_BOOTLOADER_FLASH_FROM_SD_ENABLED 1
diff --git a/libraries/AP_HAL_ChibiOS/hwdef/Pixhawk6C/hwdef.dat b/libraries/AP_HAL_ChibiOS/hwdef/Pixhawk6C/hwdef.dat
index 9ca280db8b..d7a8bd14ba 100644
--- a/libraries/AP_HAL_ChibiOS/hwdef/Pixhawk6C/hwdef.dat
+++ b/libraries/AP_HAL_ChibiOS/hwdef/Pixhawk6C/hwdef.dat
@@ -256,6 +256,10 @@ DMA_PRIORITY SDMMC* USART6* ADC* UART* USART* SPI* TIM*
 define HAL_OS_FATFS_IO 1
 
 ROMFS io_firmware.bin Tools/IO_Firmware/iofirmware_f103_lowpolh.bin
+
+# build ABIN for flash-from-bootloader support:
+env BUILD_ABIN True
+
 # enable support for dshot on iomcu
 ROMFS io_firmware_dshot.bin Tools/IO_Firmware/iofirmware_f103_dshot_lowpolh.bin
 define HAL_WITH_IO_MCU_BIDIR_DSHOT 1