Here is the methode to come back to an old version, the 1.18 for exemple:
2.Download the 1.18 firmware.
3.Put DVRFlash.exe and R8100108.118 directly onto the root of your C: drive.
4.Go to Start->Run and type in "cmd"
5.Type "cd c:\" at the command line to change your working directory to the root of the C drive.
6.Type "DVRflash X: R8100108.118" changing X to the drive letter assigned to your DVR-108 and hit enter.
7.Follow the on-screen instructions