Lenovo Yoga X1 Gen4 - Faulty Bios or what is going on?

[AYsys]

Hello dear forum members,

I own two Lenovo Yoga X1 Gen 4 laptops. One of them had a touchscreen problem, and I tried to fix it by externally flashing the BIOS. Unfortunately, I didn’t save the original BIOS and accidentally flashed it with a faulty one. After that, the device stopped working completely.

I then had the idea to make a BIOS backup from the other Yoga X1 Gen 4 (same hardware) and flash it onto the non-working device.
Nothing was flashed here — the BIOS was only backed up.

I created the backup using a CH341A Black programmer and NeoProgrammer.
When reading the BIOS chip, I disconnected the battery and then reconnected it afterwards.
However, the device no longer starts.

Now neither of the two devices works. The one that was flashed with the backup does not react at all to the power button. If I connect the power adapter without the battery, the LED on the power button blinks white 3 times and then nothing else happens.

Thank you in advance — it would be great if both devices could be brought back to life. They’re not the newest models anymore, but they have always served me well.

[SMDFlea]

Type the laptop serial numbers, full name and model, motherboard model, etc.
read the forum rules..https://www.badcaps.net/forum/troubl...before-posting

[AYsys]

Hello SMDFlea,

thank you, for your support.

This is the device from which I created (and uploaded) the BIOS backup, and it no longer starts after the backup.

Lenovo X1 YOGA Gen4
Type 20QG-S5250Z
S/N : PF-1C610G
Mainboard:
PSL10P97747
FRU:01YU380

[hoaca388]

Hello SMDFlea,

thank you, for your support.

This is the device from which I created (and uploaded) the BIOS backup, and it no longer starts after the backup.

Lenovo X1 YOGA Gen4
Type 20QG-S5250Z
S/N : PF-1C610G
Mainboard:
PSL10P97747
FRU:01YU380

X1 Yoga 4th Gen Laptop (ThinkPad) - Type 20QG

[AYsys]

Hello Hoaca388,

thank you for your support.

Unfortunately, nothing has changed. It's still the same as before. After pressing the power button, the BIOS chip receives 3.3 V at its VCC pin; before that, there is no voltage present at the BIOS chip.