I installed a new micro sd crad in my e260 and it doesn’t get recognized. I reintalled the firmware and even yelled at the e260 and still it will not work…
The e260v1 (which is what I assume you have) firmware doesn’t support SD cards >2GB, so you can’t use your card with the stock firmware.
The hardware however does work fine with cards up to 32GB though, so if you install rockbox you’ll be able to use any SD card that fits into the slot.