DFU update SD+BL SDK15.0 won't change bootloader start address

[Panchen]

Hi, 

I'm using Keil development tool.

The original bootloader start address is 0xE6000 and new bootloader start address is 0xE5000.

When I update to new bootloader, it won't change start address to  0xE5000.

it will top in after bl_activate(), you could see debug message in the below.

<info> app: Valid SD + BL
<info> app: Enter nrf_dfu_sd_bl_continue
<info> app: Enter nrf_bootloader_dfu_sd_continue
<info> app: Updating SD. Old SD ver: 6, New ver: 6
<info> nrf_bootloader_wdt: WDT is not enabled
<info> app: Verifying BL: Addr: 0x000E6000, Src: 0x0004AE7C, Len: 0x0001736C
<info> app: Copying bootloader: Src: 0x0004AE7C, Len: 0x0001736C

I get start address in the below,

>nrfjprog --memrd 0x10001014
0x10001014: 000E6000

If I set two bootloader in the same start address 0xE6000, it can update successfully.

The debug message in the below.

<info> nrf_dfu_settings: Settings OK
<info> app: Valid SD + BL
<info> app: Enter nrf_dfu_sd_bl_continue
<info> app: Enter nrf_bootloader_dfu_sd_continue
<info> app: Updating SD. Old SD ver: 6, New ver: 6
<info> nrf_bootloader_wdt: WDT is not enabled
<info> app: Verifying BL: Addr: 0x000E6000, Src: 0x0004A3C8, Len: 0x00017240
<info> app: Copying bootloader: Src: 0x0004A3C8, Len: 0x00017240

start system reset

<info> app: Valid SD + BL
<info> app: Enter nrf_dfu_sd_bl_continue
<info> app: Enter nrf_bootloader_dfu_sd_continue
<info> nrf_bootloader_wdt: WDT is not enabled
<info> app: Verifying BL: Addr: 0x000E6000, Src: 0x0004A3C8, Len: 0x00017240
<info> app: No bootloader copy needed, bootloader update complete.
<info> app: nrf_dfu_sd_bl_continue finish
<info> app: Enter nrf_dfu_app_is_valid
<info> app: Return false in valid app check

Could any one can help me to figure out, why BL start address won't change.

[Hung Bui]

Hi, 

Keil is not able to erase UICR and write new value to UICR. This results in what you observed the new bootloader flashed but the address of the bootloader in UICR is still with the older one. 

You would need to do a chip erase if you changing the start address of the bootloader. Either use nrfjprog or nRFConnect programming tool

[Panchen]

Hi Hung,

Thanks for your reply.

I can't use nrfjprog or nRFConnect programming tool to change the start address, because I can't take the product case apart.

How about if using IAR to erase UICR and write new value to UICR?

[Hung Bui]

You are saying you are updating the bootloader via OTA DFU ? And you want to  change the address of the bootloader. I don't think it's possible. Unless you modify the bootloader to do that specific task. It would be pretty complicated and with a risk of bricking your device. Do you have a lot of devices deployed to the market that requires the bootloader update ? 

if you don't have SWD connection to re-program the chip, how do you use IAR to erase and write new value to UICR ? 

[Panchen]

Yes, I want to use OTA to change bootloader start address. My customer has 30 pcs samples and no SWD connection.

I would like to update bootloader in order to use same start address in 0xE5000. This code can detect if OTA wants to update BL, then change UICR bootloader start address to 0xE6000.  Then I can update new bootloader(0xE6000).

Is it possible?

[Hung Bui]

It's possible, but it's a bit complex and requires you to have 2 step DFU update. First is to update a bootloader that erase the UICR , write new value and getting ready for the next update, then you update the new bootloader with new address. 

It's discussed in this thread. 

In your case if you only need to update 30pcs, it might be easier just open them and hook the SWD interface in ?