Use mbr instead bootloader

[Vladimir]

Hi. I have several questions about mbr.

1). Will mbr finish to write after unexpected power off?

2). Can I copy softdevice + application or only application using sd_mbr_command_copy_sd?

I can't use bootloader with communication interface because of some reasons. Application now can download the new firmware into buffer section. Will I need to use booloader just to copy from buffer (app + sd or app) or I can use only MBR?

[steve]

I can't answer the first question, but I have successfully used nrf_dfu_mbr_copy_sd() to update the softdevice and my application at the same time. To do this I generated a .bin file with the appropriate amount of padding between the softdevice and my app and wrote that to a scratch section of flash.

[Hung Bui]

Hi Vladimir,

1. No it won't be able redo the flash operation if it's interrupted by power reset or other type of reset. There is no parameter store in flash when calling sd_mbr_command_copy_sd. Parameter is stored in flash when calling nrf_dfu_mbr_copy_bl() but this API can't be used to swap application.

2. Could you let me know why you want to do that ? Note that you need to make sure the swap area to store the image is not overlapping the new sd+application area after swapping.

[Vladimir]

I want to do that because of several reasons. First - I can't use bluetooth for bootloader and any another interfaces. Because of this application should be able to write new firmware to the buffer section (dual bank sd + app or only app). If app can fill the buffer and verify, bootloader should be able to swap. So, it was the great solution to do not use custom bootloader just for copy if mbr can finish last operation. But mbr can't to do that, because of this I will need to have own bootloader to complete upgrade process after power down.

If power down interrupts softdevice upgrade can mbr run the bootloader (to finish softdevice upgrade)?

[Hung Bui]

Ok, so you want to make background bootloader that integrate into your application. My suggestion is to make a small bootloader that take the task of swapping the application (and call the MBR function to swap the softdevice). As mentioned above, the MBR won't store any information about softdevice +application swapping to flash. So if you have a power failure you screwed.

But if you have a bootloader, you can store the information somewhere in the flash and retry if there is a power failure.