Hi, may I know the model of your card?
please try following steps :
- (with the card inserted and iHost powered on) remove the card
- reboot iHost
- insert the card
please try these three steps, see if iHost recognize the card.
and please enable system logs and submit the logs via the Feedback button on Settings page.
by the way, you can have a look at this post: Firmware 1.5.5 for Sonoff iHost is available to install - #4 by Teki