Quote Originally Posted by Sirius Glass View Post
Resetting the counter is only part of the problem. The pressure plate must be in a different position because 220 does not have the paper backing that 120 has.

No Steve, in the Rolleiflex's (that can be converted) the film plane is governed by the guides that the pressure plate pushes the film 120 or 220 against, but that pesur plate must have a stronger spring mechanism

It's true that other cameras like the Yashicamat's do rotate the pressure plate but that's not necessary with the way the Rollei film path/pressure plate works.