OK.. after several tests.... I can tell you that Phantasy Starr 2 save feature doesn't work in my cart. It is a MD PRO PLUS linker. I tried Phantasy Star 4, and it works flawlessly.
For Phantasy start 2 I tested on the Genesis 1, genesis 2 and Nomad... with only one ROM in different versions of it, with several ROMS in the cart.. etc... It always had corrupted data, it could never be fixed or erased, and the save wont work. If I place a savegame converted from an emulator, and re-read it later, it is there... byte accurate (The Yuji Naka copyright is there all the time).
Any ideas?
I also notoiced someting else that is weird... In the Nomad I get, from time to time, the message that the game was designed for NTSC systems... and all I have is NTSC =P, It could even be the same ROM after another boot sequence... The Genny Model 1 I have never gives trouble though.