T420, Black screen after switching to discrete graphics in BIOS

[zoboomafo]

I was trying to get my t420 to use the Nvidia 4200m graphics in liunx so i went into the BIOS and changed the display to Discrete. Now it boots to a black screen. The back light turns of for a few seconds then goes out. It appears to be booting normally and i was able to navigate the BIOS blind to switched it back integrated. I tried to update my bios. Its now on bios version 1.52 and still has the same problem. I have a 1080p screen installed. Could that be causing the problem? Or is my Nvidia chip dead?

[zoboomafo]

Can someone confirm wether or not the discrete graphicss setting in bios works with the 1080p screen upgrade?

[RealBlackStuff]

Check the "stickies" at the top of this forum page for the FHD upgrade kits.

[zoboomafo]

I have. There is no mention of anyone attempting to change to discrete in bios. I'm just going to have to assume my Nvidia chip is dead and order a new motherboard.

[freeagent]

I'm just going to have to assume my Nvidia chip is dead and order a new motherboard.

In doing some troubleshooting, I also had that black screen happen. This on my T520. I also had nvidia disappear altogether from Device Manager. I have Win7, so not the same as Linux, but all I did, was turn power off. Then restart computer into BIOS and switch back to another Display setting. Finally got back to working system with Nvidia and Intel showing in device manager.

[cjm]

How did you navigate blindly within the BIOS? I have the same issue, but can't find my way through the BIOS nor a guide online.

[OneByteCPU]

Did you try connecting an external monitor?