Hi. I'm also looking into the SD27 and am looking for the mysterious solution to how big a card it supports. I read the manual and it only says it supports FAT16 and FAT32.

I've just researched these formats and learned that FAT32=SDHC. I suppose it's possible to make FAT32 cards that are less than 4GB, but the purpose of FAT32 is to allow capacities 4GB and higher.

This is where I'm running into trouble. I saw a customer reviewer that said he used a 4GB card with the SD27. I presumed that support for FAT32 means support for SDHC, but I decided to email Bosch technical support to get the straight answer.

Unfortunately I'm not pleased with the answer I got. They said the maximum size supported is 2GB. I complained that this doesn't make sense when the unit supports FAT32 and the whole purpose of FAT32 is to go over 2GB. I've got CD mp3, and three times the capacity is not enough to make the switch to SD. I want at least 4GB in the unit, preferably 8GB. I'm looking to not have to swap anything out anymore.

They said the reason for the 2GB limit is lack of compatibility with >2GB cards. It would have been nice if they'd given me more info instead of treating me like an idiot, but that's all I got out of them. I asked what cards >2GB would work and am awaiting a reply.

Does anyone here know exactly what the compatibility problem is?
Thanks!