Is it possible to modify BLE DFU bootloader size

[Boris]

Hi, everyone,

We develop BLE project including DFU bootloader.

But to use the standard bootloader "as is" it is not possible for us. Due to this problem we must make some modifications that require to make it bigger.

But accrording the manual in SDK the start of bootloader is defined on standard address close to the end of the flash.

Is it possible to modify the BLE bootloader to give it more space?

If it is possible which configuration files must be changed. Will it work with NRF ToolBox?

Thank you forward for paying attention

Best Regards

Boris Fridman

[Vidar Berg]

Hi Boris,

It is possible to change the bootloader start address if there is enough free space in the bootloader section. The start address is defined by the linker. Which SDK version, IC, and toolchain are you using? 

[Boris]

We are developing projects with two chips and with two SDK versions:

The first chip:

NRF51822   with SDK 12.0

and the second chip:

NRF52832   with SDK 14.0

GNU Tools ARM Embedded version 5.4.

NRFutil version 3.5

[Vidar Berg]

You can change the flash start address and size in linker script (secure_dfu_ble_gcc_nrf52.ld).

E.g., 

FLASH (rx) : ORIGIN = 0x78000, LENGTH = 0x6000 -> FLASH (rx) : ORIGIN = 0x79000, LENGTH = 0x5000 // Note: start address must be page aligned

Keep in mind that it is not possible to change the start address through DFU, so Ideally there should be some headroom in case you need to upgrade to a larger bootloader in the future.