bootloader fails with hex from Android, but OK with iOS

[Jason De Lorme]

Hi - I'm using the 51422 dfu bootloader from the nrf 6.0.0 SDK and it works fine with the iOS apps, I can send both .bin and .hex files to the device and it works fine. However, with the same exact hex file when loaded from the NRF Toolkit on Android (4.4, Dell Venue 7 & Samsung Galaxy), the download process completes 100% successfully, then it tries to jump to the start address 0x20000 of the app and it just stops, never actually reaching the app code. I've tried this with the sample hrs hex file provided and my own hex files and I get the exact same problem on Android.

What could be different between the Android implementation and iOS?

[Jason De Lorme]

After some more searching around, I found this post: devzone.nordicsemi.com/.../

I am compiling my hex with gcc and Nikita discovered that you need to set MBR size in Master Control Panel to 0.

I am using the NRF Toolbox app, but I found the MBR setting which on Android defaults to 4096. When I set it to 0, the app loads from Android! It doesn't seem that the iOS app has this setting and defaults to 0, which works. This must be the difference.

[zer0page]

This solves the issue for me as well. It seems that the new iOS version(as of Sept 2014) has the same issue and I had to switch MBR to 0 on Android to work.