if you have a different firmware and it won't load it means the bootloader is different, the file would need to be renamed to whatever the bootloader is expecting, that said though if the bootloader is different it usually means the hardware is different and they have changed it for a reason, you could end up bricking it
if it has been working ok but is now giving trouble it's more likely a hardware problem, a firmware update is unlikely to be the answer, firmware doesn't wear out, hardware does