In my college days i was designing a bootloader for avr microcontroller , i had the idea to flash code wirelessly to avr over bluetooth and also cross compile the compiler for android device so that you can code on android, every thing went well just one thing didn't, i saw that code of certain size is executing properly , greater than that size gives me wired outputs so i have to dump hex from the avr (that is flashed the by bootloader) and compaire it with the original hex of code it got messy as you can see, most fun part of this bug is that error can be anywhere cross compiler may be fucked up , the bootloader may be fucked up , or it may be my bluetooth module , after 14 hours of staring at the hex code i figured out the mess in bootloader instruction that was changing the page address for flashing .

when it worked it was 3am in night i literally burst into tears of joy next day bought myself a cake to celebrate