I want to modify x-loader / u-boot that is executed everytime the Nest boots. Therefore, I added some puts / printf and debug statements to /Dev/x-loader/lib/board.c and board/nest/diamond/diamond.c. After, I recompiled x-loader and used the shell script. However, it seems like only some changes are reflected only during the boot phase of the attack (not the standard boot process) after switching to DFU mode and executing the attack.sh. So my questions are the following:
1. How can I influence x-loader that is executed during "standard" boot (not the attack boot)?
2. I only seem to be able to use printf/puts/debug in lib/board.c. Contrary, it is not possible to ouput anything at line 282 in board/nest/diamond/diamond.c even though there is already a printf() command at line 281 (printf("\n SDRC Register Dump:\n");). *
3. What is the difference betweens puts(), printf() and debug()?
* I also added fflush(stdout) to enforce that the buffer content is written to stdout.