How to change the mbr jump address location

[R_S]

Hi,

I am using nrf5280 development kit and 17.1.0 sdk.

i am working on  ble_app_uart example code.

Its working fine no issue. Since the start address of the application is 0x27000 and i want to change it on to some other location as per my requirement which id 0xE8000.

But when i changed the starting address then its not working. Looks like control not reaches to that location.

or 

mbr not able to jump that location which i changed. 

can someone help me here. what exactly i am missing here.?

Regards

R_S

[Einar Thorsrud]

Hi,

How do you try to jump to 0xE8000?

Without knowing more I suggest you refer to the bootloader in nRF5 SDK 14.2.0 (more recent SDK versions use a different approach). You can refer to the implementation of <nRF5 SDK 14.2>\components\libraries\bootloader\nrf_bootloader_app_start.c you can see that nrf_bootloader_app_start() here takes any application start address and the way it configures the MBR and SoftDevice is different from more recent SoftDevices. You should use this approach, which can also be used with later SDK versions.

To be more specific, In SDK >= 15.0.0, the boot process consists of forwarding interrupts to the SoftDevice using SD_MBR_COMMAND_IRQ_FORWARD_ADDRESS_SET (nrf_dfu_mbr_irq_forward_address_set()), and then always jumping to address 0x1000 (SoftDevice start) instead of the application start address. The old approach is to use the SD_MBR_COMMAND_INIT_SD and SD_MBR_COMMAND_VECTOR_TABLE_BASE_SET command, and start the application at a specific address. This is what you should use when the application is not always immediately after the SoftDevice.

You can compare components\libraries\bootloader\nrf_bootloader_app_start.c in SDK 14.2 and a newer SDK to see both approaches.

Einar