I believe he was refering to the hacked Windows flashing firmwares from CDR-Info.
The ZSxx goes for the LTR-40125S and the VSxx for the LTR-48125W models.
Available firmware updaters for 40125S->48125W conversion:
ZSxx to VS02
ZSxx to VS04
ZSxx to VS06
Available firmware updaters for 48125W->40125S conversion:
VSxx to ZS0A
VSxx to ZS0J (Adds Mt. Rainier and P-CAV recording technology)
VSxx to ZS0K
The actual download links a sporadic at best as the majority of the time you will not be able to connect to the remote server.