Giddy to smear some Ice Cream Sandwich on your Asus Eee Pad Transformer Prime, only to see the words "Serial Number Not Found" crush your dreams and deny your upgrade? Asus' Gary Key says the company is aware of the issue, has successfully reproduced the bug, and is working on a fix. The issue doesn't affect all Prime tablets — we got our upgrade right away — but if the Asus servers are giving you bad news and you see "unknown" in the About tablet > Status page, the company recommends you do a full Factory Data Reset from Settings > Backup and Reset, then leave the unit running for a full fifteen minutes with the screen on so the device can sync with the update servers. You can follow the official Asus thread for updates on the situation at our source link.