Long story short:
Two EZ4: old miniSD version, new TF version
Four cards: SanDisk miniSD 512M, Verbatim TF 2G, Toshiba TF 8G, Kingston TF 8G
EZ4 miniSD 1.77: SanDisk 512M doesn't work, the other three(in a miniSD-TF adapter) work.
the SanDisk 512M works on 1.74 and still works in firmware...