I bought a no-name 4GB SD card for my Treo 700p, and it's really flaky: at somewhat random (but frequent) times, it makes the "you just ejected the card!" noise, and then I have to pop it out and back in again to get it to be recognised. I think maybe it only does this when it's not being accessed, e.g., as soon as I stop playing music and/or the device goes to sleep, it unmounts the card. I haven't had it do it while listening to music, but then as soon as I pause and the phone goes idle, blam.
The card seems to work fine when I plug it into a USB reader on my Mac. I also tried reformatting it. Some googling suggests that there are people out in the world successfully using 4GB FAT32 SD cards with the Treo 700p. Palm's site says they "have not tested" 4GB cards, though.
So is there some less sketchy 4GB card I should buy instead? Or does this trick just not work?
Update: Bought a Transcend 4GB. Works fine.