Yes.
As I've stated in the video and in the installation instructions, you must backup the Flash after installing the firmware, so that if you want to restore to the official firmware, you have a backup of the Flash memory which contains all codeplug data etc
If you do not backup, the Flash, and then reinstall the official firmware, you won't be able to use the radio, becuase the radio says a password lock has been applied
This is because the codeplug of the OpenGD77 overwrites the password lock code memory which the offficial firmware uses.
I think there is a work-around for this, as documented for the MD-9600, for people who did not backup their Flash memory