Thanks for the reply Islander

Here's what I have
TiVo 1: OzTiVo mod, software 11.3b8, 2TB drive
TiVo 2: OzTiVo mod, software 11.3b10, 2TB drive, MAK key
TiVo 3: pre-modded, software 11.3b10, 320GB drive (this TiVo is not currently used)

I have a TBK file of TiVo 2 and could make a TBK file of TiVo 3. Which of those is preferable to use for upgrading the software on TiVo 1?

What will happen to any recordings currently on TiVo 1 when I restore the TBK file from one of the other TiVos?

Appreciate your help
RLSA