T15 won’t boot from USB or HDD

[Pmidas]

Hello
I am writhing this to ask for a help for a laptop that I recently got (company was selling their old stuff to employees)
So I got the laptop with windows installed on and wanted to remove secure boot and all the fluff that was previously there as bios/eufi settings. I turn off all security related settings and deleted then restored secure boot keys. From that point the machine can enter bios but will not boot from USB - screen goes black (did try few usb sticks - they work on my P50 laptop). exchange the 2 M2 drives from my P50 and T15 - P50 booted the windows that was on T15. T15 did not recognize the P15 M2 drive. Removed the cover of the T15 to get the BIOS chips info and I am wondering if requesting files for those, purchasing a programmer and attempting to flash bios with it without resoldering (using clamps ).
If anyone has an idea what could be wrong or if I am on the right track - let me know please

[ogopogo]

Late reply, but try updating the BIOS, and booting on UEFI only with secure boot disabled a live Linux distro like Ubuntu, Linux Mint, Fedora, Debian, etc. Within it, you can use efibootmgr to see if you have the correct entry for Windows on your NVRAM. Maybe your BIOS doesn't know where your boot EFI partition is.

I don't know if you can safely hardware flash the firmware BIOS on this model.