Thinkpads Forum

My x220 tablet has died, at least the screen doesn’t work and I’m looking for possible solution how to fix it before swapping the mobo (x230t is an option).

I have flashed the coreboot BIOS several years ago and was very happy with it. Until recently, when it started to give strange sings of wear or some system failure. System wouldn’t turn off completly (it constantly switched itself on if plugged to power adapter) and the sleep led wouldn’t ever go off. Battery LED was always amber, despite the battery having enough juice for some hours work. Also, kernel kept sending the „dazed and confused” message.

The last symptom has dissapeared after uninstalling some fan control package from my Debian. Investigating possible causes of strange LED behaviour and switchin on jus by itself I came to idea that this issue may be EC related. I remember playing with ectool and it’s highly possible that in the past I have tweaked some values just to see what would happen.

The only way of reversing to original EC ROM that I’m aware of is flashing the original firmware back again and doing official Lenovo system bios update. To my dissapointment the Lenovo bioses (old, new, hacked, vanilla) refuses to boot, outputting the Thermal Sensing Error. So, until now I’m unable to flash the original bios so to have the EC brought to factory defaults.

And after flashing the coreboot image back, the lcd panel stopped to work. I can’t see anything on screen (neither backlight nor any traces of desktop). External monitor works and system reports LCD, xrandr detects display modes (I have tried with cable in and out). Also new EC symptom has appeared. While turning the device on the bluetooth LED goes up gradually, in course of second or two.

I would like to ask your help. Please, someone using same x220 tablet do dump contents of your EC memory (debian ectool -d with kernel parameter iomem=relaxed set on boot) and post it here. I hope there is a screen switch bit I can manually set on my system. Any other advice would be also welcome!

PS interesting symptom is that after flashing original 1.31 or 1.42 system boots to POST even with 1833MHz dram installed.
PS2. How to check if LVDS ribbon works well?

Didn't some X220's suffer from some kind of EEPROM issue? I wonder if this is related to that?

Flashing opensource BIOS like coreboot or libreboot always means manipulating the contents of the EEPROM. I think the whole low level software and data are shared by several chips soldered onboard. Certainly the EC ROM isn't loaded into the only SPI chip I can easily access with my external programmer.

Small update, the screen outputs image but it's backlight that doesn't go on. It also doesn't respond to keyboard controls :/

Somewhere in my parts stash I have a bare X220T motherboard (04W1534) with i5-2520M from a 4296-2WU.
Let me know if interested.

RealBlackStuff wrote:Somewhere in my parts stash I have a bare X220T motherboard (04W1534) with i5-2520M from a 4296-2WU.
Let me know if interested.

Thx but I wont try another mobo until I’m sure that this is not panel backlight issue.

Hi, if you plug in an external monitor that should give you an idea if it's just the backlight or not. I'd expect any of DVI/HDMI/DP plugged via the right cable into the DP output to be automatically detected and used if the mobo is healthy enough. If you have 4337 docking station or similar around that's another way to plug the monitor in. I fear you may eventually find that you indeed need to swap the mobo, but it's just my guess.

atagunov wrote: ↑

Wed Mar 10, 2021 9:04 am

Hi, if you plug in an external monitor that should give you an idea if it's just the backlight or not. I'd expect any of DVI/HDMI/DP plugged via the right cable into the DP output to be automatically detected and used if the mobo is healthy enough. If you have 4337 docking station or similar around that's another way to plug the monitor in. I fear you may eventually find that you indeed need to swap the mobo, but it's just my guess.

It worked, after plugging the screen and pressing fn+f7 several times the laptop display went back on. Thx, I owe you a beer