Let me put it this way - changing sd card helps, but just putting sd or sdhc card won't work. Old 2G or less in size cards tend to work (with os V2 on all gameboys, classic, color or advance), but this recommendation is not bulletproof. It may work with osv2, and it may not.
of course my list is not bulletproof
you should ask to SanDisk why their fastest card have bad "Access Time"
2GB SD card has Spec version 1.01
like other users said
not all sd card(s) made with the same parts
some will fail, most will work
also about
gbc and gba slot(s) access time and power supply are not made equal
will cause different results, most will work for others, some will fail
I update my list to be more detail
http://krikzz.com/forum/index.php?topic=3395.msg32603#msg32603beside that, there are many sdcard fakes on the market, even on amazon or local stores. ^^
it's not always easy to tell if the sdcards are genuine ones or not.
so if your card is on an incompatible list, it's still worth a try. :>
SD card is Spec version 3.01 or higher are not backward compatible
Everdrive compatible with SD card is Spec version 2.00 or older
I update my list to be more detail
http://krikzz.com/forum/index.php?topic=3395.msg32603#msg32603