Migrate bootloader from SDK 11 to SDK 13

[Alex Takiev]

Hello,

I have an application based on SDK 11 and Softdevice v2.0.0. Also there is a legacy bootloader from SDK 11 for performing DFU.

I am wondering whether it is possible to perform DFU of my devices in the field with old DFU and update all components of my firmware? I have ported the application to SDK 13 and validated that it works as expected with SD v4.0.2.

But I have no idea how to prepare zip-package for DFU in order to update SD + APP + BL. Should I pack new Softdevice and application with old DFU or this pack should be splited into pieces?

Now legacy bootloader occupies 16K of flash and resides at 0x7A000. If I am not mistaken in order to move to the new secure bootloader I should have reserved 24K. But it is not possible to use J-link to reprogram the devices now. Is it possible to perform DFU to modern firmware with legacy bootloader?

Thank you.

[bjorn-spockeli]

Hi Alex,

Yes, it is possible, but it is not failsafe, see this answer.

Best regards

Bjørn

[Alex Takiev]

Hello Bjørn, Thank you for your response. Am I right that I should do following steps:

• apply dfu_dual_bank_with_fix.c from this answer to the legacy bootloader which is based on SDK 11

• apply that fix by performing DFU of bootloader only

• build custom bootloader by using provided files [here] (devzone.nordicsemi.com/.../), change its address from 0x7A000 to 0x78000 in order to be able to upload the new secure bootloader

• apply that custom bootloader to my devices

• prepare zip package with new SD v 4.0.2 + APP + secure BL

Is it correct?

[bjorn-spockeli]

Hi Alex, you can combine the fix for the page alignment issue with the legacy to secure bootloader workaround, i.e.

• build custom bootloader with page alignment fix and legacy to secure workaround by using provided files [here] (devzone.nordicsemi.com/.../), change its address from 0x7A000 to 0x78000 in order to be able to upload the new secure bootloader
• apply that custom bootloader to my devices
• prepare zip package with new SD v 4.0.2 + APP + secure BL

[Alex Takiev]

Hello Bjørn,

Thank you for your response! I built custom bootloader from the topic you've noticed and create zip package with the bootloader only with nrfutil 0.5.3:

nrfutil dfu genpkg --bootloader custom_bl.hex custom_bl.zip

After I applied it via nRF Connect my device cannot start at all.

[Alex Takiev]

Bjørn,

As you may expect, I've also changed custom bootloader start address in Keil project from 0x7A000 to 0x78000.