Signing image and CONFIG_ROM_START_OFFSET parameter.

[JuanAlm]

Im working with nrf52840DK and nrf Connect SDK 2.2.0. 

My goal is running this sample. (SMP server sample). Let's check the described steps:

1º) I have installed the MCUMGR CLI

2º) I have built and flashed the MCUBoot

3º) I have built the sample application with the next command:

west build -b nrf52840dk_nrf52840 zephyr/samples/subsys/mgmt/mcumgr/smp_svr -- -DOVERLAY_CONFIG='overlay-serial.conf;overlay-fs.conf;overlay-shell-mgmt.conf'

4º) This step is where I got stucked... Trying to signing the image. When I run the next command:

west sign -t imgtool -- --key bootloader/mcuboot/root-rsa-2048.pem

I get the next prompt:

D:\ncs\v2.2.0>west sign -t imgtool -- --key bootloader/mcuboot/root-rsa-2048.pem
=== image configuration:
partition offset: 49152 (0xc000)
partition size: 421888 (0x67000)
rom start offset: 0 (0x0)
=== signing binaries
unsigned bin: D:\ncs\v2.2.0\build\zephyr\zephyr.bin
signed bin:   D:\ncs\v2.2.0\build\zephyr\zephyr.signed.bin
Usage: python -m imgtool sign [OPTIONS] INFILE OUTFILE
Try 'python -m imgtool sign -h' for help.

Error: Invalid value for '-H' / '--header-size': Minimum value for -H/--header-size is 32
FATAL ERROR: command exited with status 2: 'C:\Users\juan.martinez\AppData\Local\Programs\Python\Python38\Scripts\imgtool.EXE' sign --version 0.0.0+0 --align 4 --header-size 0 --slot-size 421888 --key bootloader/mcuboot/root-rsa-2048.pem 'D:\ncs\v2.2.0\build\zephyr\zephyr.bin' 'D:\ncs\v2.2.0\build\zephyr\zephyr.signed.bin'

I noticed the --header-size is 0 and it should be (the prompt says it) minimun 32... What is the exactly minimun value for it? How can I change it?

[Hung Bui]

Hi Juan, 

As the log suggested the minimum header size should be 32. 
Could you please try: 

west sign -t imgtool -- --key bootloader/mcuboot/root-rsa-2048.pem --header-size 32 --pad-header

Please note that by default if you build the image that has MCUBoot, the image is signed automatically and you can find the binary that signed and ready for DFU transferring. Please look for app_update.bin in the build folder. You don't have to call west sign to sign the image. You can also change the key if you want by modify the config option. 

Please see here: developer.nordicsemi.com/.../readme-ncs.html

[JuanAlm]

Nice! Now it can be signed correctly and zephyr.signed.bin has been generated and flashed!

But now appears a new problem, I cant echo nothing:

 

root@gcu1:~# mcumgr --conntype serial --connstring "/dev/ttyACM0,baud=115200" echo hello
Error: NMP timeout

root@gcu1:~# mcumgr --conntype serial --connstring "/dev/ttyACM1,baud=115200" echo hello
Error: NMP timeout

ACM0 and ACM1 are the ports that appears when I connect the nrf52840DK. I have disables Mass Storage Device.

[Hung Bui]

Hi Juan, 
We need to check what you flashed. Did you flash the merged.hex ? You can modify the application to do some activity just to know that it's working. 

I would suggest you to follow the guide here to integrate the SMP protocol to your application: https://devzone.nordicsemi.com/guides/nrf-connect-sdk-guides/b/software/posts/ncs-dfu#serial_dfu

[JuanAlm]

Following the sample I mentioned before, I builded the sample app, signed it and then I flashed the "zephyr.signed.bin" file created.

I tried flashing the mergex.hex file and getting the same error, no echoing.

I tried your suggestion and I think I have discovered the problem in the next step:

• Get the development kit’s serial port name (for example, "/dev/ttyACM0"), by running nrfjprog --com

I get the next prompt:

root@gcu1:~# nrfjprog --com --log
[error]: [SeggerBackend] - Error in dlopen: libjlinkarm.so: cannot open shared object file: No such file or directory
[error]: [SeggerBackend] - Dll failed to open.
ERROR: JLinkARM DLL load failed. Try again. If it keeps failing, please
ERROR: reinstall latest JLinkARM from Segger webpage.

[Hung Bui]

Hi Juan, 

I would suggest to test UART example before you move to DFU example. 

Are you testing with Linux or Windows environment ? If you just run nrfjprog.exe what happen ? 

Have you installed Jlink ? 

Note that when you flash the application you should flash merged.hex ,the  sign image is only used when you send the image for DFU.