Custom bootloader with softdevice with jump to a specific address of app

RE: Custom bootloader with softdevice with jump to a specific address of app

marklander — Mon, 15 Jul 2024 13:55:29 GMT

Got it working! Thanks for your support!

RE: Custom bootloader with softdevice with jump to a specific address of app

Vidar Berg — Mon, 15 Jul 2024 13:29:31 GMT

[quote user="marklander"]SD_MBR_COMMAND_IRQ_FORWARD_ADDRESS_SET and then jump always to 0x1000[/quote]

This approach only works when the application starts at the default address (default start address is hardcoded within the Sotdevice).

The SD_MBR_COMMAND_INIT_SD is needed to initialize the Softdevice and make the MBR start forwarding interrupts to it. After the Softdevice has been invoked with this command, the bootloader can instruct the Softdevice to relay application interrupts to the application's vector table with the sd_softdevice_vector_table_base_set() function. The bootloader must then branch directly to your application's reset handler.

RE: Custom bootloader with softdevice with jump to a specific address of app

marklander — Fri, 12 Jul 2024 08:49:19 GMT

[quote userid="4240" url="~/f/nordic-q-a/112868/custom-bootloader-with-softdevice-with-jump-to-a-specific-address-of-app/493578"]It looks like everything is working correctly up until the point where you try to make the "jump" to the application. Are you able to step through the app's start function with a debugger to see what happens?[/quote]

Will try and see if I can use debug with Rust, for the jump i am using this implementation let me know if it seems correct...

[quote userid="4240" url="~/f/nordic-q-a/112868/custom-bootloader-with-softdevice-with-jump-to-a-specific-address-of-app/493578"]Another thing you can try is to call 'nrfjprog --readregs' after the jump to the main app to read out the core registers. This may provide us with some clues as to what the problem is.[/quote]

Will try tonite at home

Anyway looking to different posts like this i am bit confused if i need also to call the isr forward of mbr command like I see in this post.

And also this post seems indicating that both approach can be used:

SD_MBR_COMMAND_INIT_SD and then sd_softdevice_vector_table_base_set

SD_MBR_COMMAND_IRQ_FORWARD_ADDRESS_SET and then jump always to 0x1000

Anyway thanks for support, i will continue my investigation...

RE: Custom bootloader with softdevice with jump to a specific address of app

Vidar Berg — Fri, 12 Jul 2024 08:07:28 GMT

It looks like everything is working correctly up until the point where you try to make the "jump" to the application. Are you able to step through the app's start function with a debugger to see what happens?

Another thing you can try is to call 'nrfjprog --readregs' after the jump to the main app to read out the core registers. This may provide us with some clues as to what the problem is.

RE: Custom bootloader with softdevice with jump to a specific address of app

marklander — Thu, 11 Jul 2024 21:49:00 GMT

[quote userid="4240" url="~/f/nordic-q-a/112868/custom-bootloader-with-softdevice-with-jump-to-a-specific-address-of-app/493237"]Issue the SD_MBR_COMMAND_INIT_SD command through the sd_mbr_command() API. This will cause the reset handler of the Softdevice to be executed.[/quote]

Hi Vidar Berg ,

probably i am missing something...

I tried your sequence and I still cannot see app starting...what i see is:

SD_MBR_COMMAND_INIT_SD return 0 - so seems executed correctly ( maybe I did not specify that i don't us sd in bootloader, but I don't think I need to enable it )
Disabled all interrupts.
sd_softdevice_vector_table_base_set also returns 0 so seems correct...
At the end i tried to jump to main app start address and also to 0x1000 but nothing seems happening...

Any advice on the sequence i made?

RE: Custom bootloader with softdevice with jump to a specific address of app

marklander — Wed, 10 Jul 2024 19:53:58 GMT

Ups! I got now that I am confusing sd_mbr_command_vector_table_base_set_t with sd_softdevice_vector_table_base_set!

So sd_softdevice_vector_table_base_set will take the starting address of application with offset...and then I have to jump there

RE: Custom bootloader with softdevice with jump to a specific address of app

marklander — Wed, 10 Jul 2024 19:08:52 GMT

Thanks! I will try the exact sequnce you are suggesting.

One thing i forgot...i am on rust. But i have all bindings to nrf mbr so i can emulate all the sequence.

Two questions:

What does the sofdevice SD_MBR_COMMAND_INIT_SD do exactly?

I have used sd_softdevice_vector_table_base_set function and seems that calling this a reset is issued immedeately ( while irq fuction does not reset ) am i right?

And do i need to reserve a flash page for settings for that command?

RE: Custom bootloader with softdevice with jump to a specific address of app

Vidar Berg — Wed, 10 Jul 2024 17:45:06 GMT

Hi,

Yes, this is possible. However, rather than using SD_MBR_COMMAND_IRQ_FORWARD_ADDRESS_SET, you can use the SD_MBR_COMMAND_INIT_SD command. This will allow you to use the sd_softdevice_vector_table_base_set() function in your bootlaoder and change to a non-default interrupt forwarding address for the Softdevice. The application start sequence in the bootloader should be something like this:

1. Issue the SD_MBR_COMMAND_INIT_SD command through the sd_mbr_command() API. This will cause the reset handler of the Softdevice to be executed.

3. Disable interrupts globally

2. Now with the SD initialized, you can use sd_softdevice_vector_table_base_set() to set the Softdevice vector forwarding address to your application's vector table address.

3. Forward execution to main application.

Best regards,

Vidar