Unable to Update Bootloader Using DFU

[Cory Mast]

Hello,

I am trying to update my bootloader using DFU and I am running into a few issues. I have successfully flashed and tested my current bootloader on my board and everything is working great. In an attempt to prove that I have bootloader updates over DFU working correctly, I took the same hex file that was flashed to my board (with the exception that I changed the advertising name) and used it with nrfutil to create a zip package. I then use the nRF Connect Android app to DFU my device. I am able to achieve two different errors when I try to update the bootloader on my board with the following two methods:

1. I choose Distribution Packet (ZIP) as my method for updating my bootloader and then hand it the zip file that was created with the nrfutil tool. I receive the following error

Remote DFU error: REMOTE DFU DATA SIZE EXCEEDS LIMIT

2. I Choose Bootloader as my file type and then select the hex file for the updated bootloader and I select that dat file that was in the output zip file from nrfutil. The bootloader progress reaches 100% and then I receive this error

Remote DFU error: REMOTE DFU INVALID CRC ERROR

Can I not use the dat file that was in the nrfutil output zip file as the init packet for my bootloader update? I am also confused as to why i'm getting the size limit error if it is the exact same hex file with the same flash usage and settings. I understand that I can't grow the bootloader beyond it's initial size, but if it is the same size that shouldn't be a problem right? One interesting thing that I discovered is that if I use the Zip file, nRF Connect reports the image size as 16384 bytes total; if I use the hex+dat file, nRF Connect reports the image size as 13108 bytes total.

Here are the specifics related to my project:

• SDK11
• SoftDevice S130 V2.0.0
• nRF51822-CFAA variant
• Bootloader IROM1 Start: 0x3C000
• Bootloader IROM1 Size: 0x3C00
• Bootloader Region Start: 0x3C000
• Bootloader Settings Address: 0x3FC00
• nRF Connect for Android (v4.7.0)

Any assistance you can provide with helping me understand and getting me past these DFU errors is greatly appreciated.

Thanks and Best Regards, Cory Mast

[bjorn-spockeli]

You should only set the BANK_VALID_APP flag when you flash the bootloader with a programmer. You need to remove it when you create firmware images, otherwise you add the entire bootloader settings flash page to the image. The maximum bootloader image size is BOOTLOADER_REGION_START - BOOTLOADER_SETTINGS_ADDRESS, i.e. 0x3FC00 - 0x3C000 = 0x3C00.

[bjorn-spockeli]

Happy to help :) I would appreciate if you could mark the answer as correct/accepted by clicking the checkmark in the circle to the left of the answer.