bootloader only works when firmware installed by dfu ota

RE: bootloader only works when firmware installed by dfu ota

martial — Wed, 29 Jul 2015 06:10:25 GMT

Hi People,

I face a similar problem like this. Once doing a DFU OTA, I get a message from nrf toolbox stating the transfer has been successful but I find the device to be still in bootloader and not jumping to application. Is the problem that I state is similar to that mentioned in the thread? I use SDK9.0 with SD8.0 and nrf51822 Rev 3 chip.

RE: bootloader only works when firmware installed by dfu ota

John — Fri, 18 Jul 2014 13:29:21 GMT

I was programming the app with the Keil IDE and the bootloader with nrfjprog, but what you have there should work as well.

RE: bootloader only works when firmware installed by dfu ota

tim — Fri, 18 Jul 2014 00:28:31 GMT

Thank you that does appear to be the problem.

I assume programmed the bootloader and the application together as follows.

nrfjprogj.exe --reset --program blootloader.hex application.hex --verify

RE: bootloader only works when firmware installed by dfu ota

John — Thu, 17 Jul 2014 21:17:57 GMT

A while back I noticed that any time I programmed my application FW using Keil or nrfjprog, and the chip had previously been upgraded with the bootloader, the chip would get "stuck" in the bootloader. What was happening was that when the chip was bootloaded, the bootloader calculated and stored the CRC of the application FW it programmed. When the bootloader runs after a reset, it recalculates the CRC of the application FW in memory. If this CRC doesn't match the one it stored on the previous bootloader it will not jump to your application.

So, if you bootload a device and then later reprogram it with an external programmer you will see the problem you are having. So you either need to bootload the application again, or find a way to erase the CRC the bootloader has stashed away. I did the latter by reprogramming the bootloader when I reprogrammed the application.