It took a little bit of doing, but I -did- actually get my EDGB working on my Super Game Boy 2. I looked around the forums and tried cleaning the connectors as was suggested and that worked great! For exactly one boot up. Then I kept getting either an immediate Red-X Cartridge w/ Garbled "NINTENDO(TM)" text -or- it'll do the Super Game Boy 2 bootup before giving the "no cart loaded" icon. So I cleaned it again and it worked! ...for one boot up.
I don't know why I have to clean the dang thing every time I power off, but that's what I have to do. If I put it in my Super Game Boy 1 it works just fine, even before I tried cleaning anything to begin with. And I'd think it was the way I'm seating the cartridge, but it boots up first try every time I clean it, once, and then no amount of fiddling makes it work until I clean it again.
I'm cleaning both the Game Boy-SGB2 connector as well as the SGB2-SNES connectors each time...I'm not sure what's going on. It's a pain, but if I gotta do it this way I gotta do it this way, but I'm wondering if I'm covering up a bigger issue and one-day-after-return-period (because that's how it always works) I'm gonna be outta luck because it's been over-cleaned and something broke or something like that. Any advice?