X220 suspend issue, and possible solution

[axur-delmeria]

Not long after I got my X220, I noticed a strange quirk: when it's on standby/suspend for more than 15 minutes, the Power indicator LED turns off, and upon resuming, wifi is disabled and Fn key-combinations don't work. It takes a restart to get things back to working order.

At first I thought it was just a Windows quirk (I installed Windows in a hurry, and may have left out some Lenovo software), but after getting an mSATA SSD and installing Debian 8.0 , I discovered that it also happens under Linux. :O

I reset the CMOS settings to default, and played around with some settings (LAN Option ROM, Always-On USB, etc.) to see if the problem would go away, but it didn't.
At that point I wondered if it's a hardware issue, and whether I'd have to part with such a wonderful machine in less than half a year. Then I got an idea: why not check the output of dmesg after the problem occurs? Maybe I could find some clues. Sure enough, an error message concerning the EC (embedded controller) popped up.

So I rebooted and entered BIOS setup. There I noticed that the BIOS version was 1.20, but the EC firmware version was 1.09, which was rather unusual. A quick look at Lenovo's support website showed that the v1.20 BIOS came with a newer version of the EC firmware than the 1.09 that mine had. I decided to download the newest BIOS, and even took a gamble by flashing it while running 64-bit Windows. :O

Luckily my X220 survived the BIOS flash, and here I am now typing this post. I haven't run into the issue so far (I entered suspend and left it for around half an hour), but I'll run a few more tests in the coming days.

[axur-delmeria]

I just put it in suspend for more than an hour last night and it looks like the problem is gone!

The only question that remains: how and why did this X220 have an odd combination of BIOS and EC firmware version?