uno capatible board error when uno bootloader

i have a uno compatible board from china at first it worked fine but after a whil it gave this error:
avrdude: verification error, first mismatch at byte 0x0119 0x11 != 0x24 avrdude: verification error; content mismatch

i saw somewhere it was something with the bootloader so i flash the nano bootloader and it worked fine the the uno one doesnt.

thanks in advance