RE: something about MBR

Hung Bui — Mon, 09 May 2022 09:18:34 GMT

Hi Grandpa,

The compiler can automatically detect the start address of the bootloader from your configuration using this:

#define CODE_START ((uint32_t)&Load$$LR$$LR_IROM1$$Base)

This CODE_START is assigned to BOOTLOADER_START_ADDR in nrf_bootloader_info.h

Then the BOOTLOADER_START_ADDR is written to 2 places in flash:

1. To UICR (UICR_BOOTLOADER_ADDR address 0x10001014) using __attribute__ syntax , see nrf_bootloader_info.c

2. To MBR internal setting page at 0xFF8, using a flash write inside nrf_bootloader_mbr_addrs_populate() function in the same file.

The MBR internal setting has higher priority compare to the UICR.

Every time you change the start address of the bootloader, make sure you do a chip erase so that these information can be written with a new value.