after this i reboot whitout the SD and i get: error in mount_flash: mount_common: could not mount /dev/system
Okay, now you should try to mount the system partition under the system running from the SD card:
Code
mkdir /tmp/system
mount -o ro /dev/system /tmp/system
md5sum /tmp/system/SYSTEM
md5sum /flash/SYSTEM
If it was successful and the two SYSTEM file checksums match each other (expected value: 23bec528ae6e75828fa5126c8663b6e1), then we continue in another direction, but if we do not get the expected result, then we have the cause of the problem.