Sorry to ask two questions in a row.
I bought a Transcend Class 10 Premium 400x MicroSD card that was incompatible with my Mega ED & Turbo ED. Is it likely that it won't be compatible with the GBA ED as well? I've found that Class 4 and 6 work perfectly...just wondering if I should get a "lesser" MicroSD card in preparation for the GBA ED.
Thanks!
Transcend is a crap brand; do not use. Stick to Kingston, PNY, or Sandisc.
I used Class 10 PNY cards in my Super Everdrive v2 (8Gb), Everdrive MD (8Gb), and Everdrive 64 v3 (32Gb) and all work beautifully. The N64 ED loads Conkers in 3 secs!

My GB ED and Turbo ED have older 2Gb micro SD cards, and my N8 (Famicom) have an older 4Gb micro SDHC in it as well. All my SDHC cards are formatted FAT32, though the older 2Gb cards may be FAT.