Probook 4740s boot problem after bios update

[facelessone]

I have installed Windows 10 on 4740s and after I could not get switchable graphics to work I updated the bios to latest version F67 rev. A.  in hope it would help, and there comes the problem.

After the bios was flashed you get a screen saying the laptop will reboot, leds will flash and so on. Laptop rebooted but it hanged in some kind of endless boot/restart loop. You can see it in a video, it goes on for and hour if I leave it like that. It restarts, fan barely starts and reboots again.

I can get it to boot if I remove a memory module, add aditional memory module, change memory module slot, and that time it will boot normally to windows. I can restart the laptop from windows and it will boot normally. If I turn it off, it won't boot again until I mess with memory modules.

I have tried downgrading BIOS but it won't let me.

I have tried flashing BIOS again but the problem is the same.

I have tried bios recovery but it doesn't lead to bios flashing screen,  It says "A system BIOS recovery has occured. BIOS recovery (500)."

When following the instruction to recover a BIOS holding Win + B key, pressing power and holding Win + B until a recovery screen appears, laptop reboots as long as I am holding Win + B keys, and boots after few restarts and says that message after I release Win + B.

Laptop was working fine until BIOS update.

https://www.youtube.com/watch?v=FG7BtLFy_aE

[parados]

Similar thing happened to my prayer-book 4740s after I updated BIOS to ver. F67 rev. A. Laptop could not load the OS from HDD or boot from any other device (SD card or DVD).
After flashing the BIOS again to ver. F67 rev. A Iaptop successfully loaded OS, but still can't boot from any other device. DVD drive can't read any media though it worked just before BIOS update . SD card slot works in Windows but I'm unable to boot from it. If SD card is in the reader during reboot Caps lock flashes five times repeatedly and after certain time boot sequence continues. BIOS update log contains "Failed init of SMBIOS data" after each update to ver. F67.

My AMD gpu failed a long time ago and when Iook at laptop info in BIOS I can only see Intel gpu bios version second gpu (AMD) bios version field is blank.

Did you manage to solve your boot issues? Can you boot from SD card?

[facelessone]

BIOS chip got corrupted. Changing the chip and reprogramming it outside the machine on programator solved the problem.

Programing the original chip went okay on the ouside programator,  but verifying not.

[parados]

Thanks for the quick aswer, I'll probably have to do replace bios chip as well.

Do you see GPU BIOS versios for both AMD and inegrated Intel GPU in laptop info?