What bootloader done before run main app ?

[patiphan]

Now I found a lot of module stuck in fatal exception (3) as shown below.

img_1

fatal exception.jpg (120.57 KiB) Viewed 3832 times

I observe that the module crash after boot the main app code from flash memory.

Compare with the good one in img_2, I curious that what the bootloader actually does in the red circle ?

img_2

boot_log_good.png (35.81 KiB) Viewed 3832 times