data1701d

Like others have said, I just use two drives, and I can boot into Windows with GRUB.

However, these days, I just do a VM with GPU passthrough. (I installed a second graphics card in my PC just for this.)

The last thing I would try is seeing if you can update/revert the firmware on this thing.

If not, then I think I might be out of ideas unless you happen to have a KVM switch that can stream over le intwerbz.

Have you tried completely resetting all BIOS settings?

Okay. What does your Config > USB look like?

I have almost the same model (it's basically just the 16" version) and I can boot a USB just fine under secure boot.

These settings seem exactly the same as mine in all significant ways. Can you show me a picture of Config > USB?

Also, what's the partitioning on your laptop like? Have you actually set up Windows, or have you just left it in OOBE mode for now? On my E16, I just put in a second drive and haven't even touched Windows yet.

Also, when I get time today, I might try replicating your steps with Ventoy to see what happens. Have you just tried straightup flashing an image? (If you haven't, probably try something like OpenSUSE or Debian, which tend to have better EFI support on their installers.)

Could you record a video showing the steps you take to try to boot the USB?

Also, maybe pictures of any BIOS settings. I want to see if I can replicate the problem on my laptop.

This seems like a very recent laptop.

Could MBR be your problem somehow? Maybe it needs to be a GPT table instead.

Weird. What distro is on it, what program did you flash it with, and does it show up in the file manager on another machine?

I have basically the same laptop (it's an E16, but with the same CPU - it's just the 16-inch version of your laptop). Make sure you press enter, press F1 to go into BIOS, then go into Security > Secure Boot and enable "Allow Microsoft 3rd Party CA". That worked like a charm for me.

If you're still having problems, try writing down the steps you have taken (down to the key combinations; some pictures would be nice as well). I should have all the same settings menus.

Don't worry, though, you've made a good choice; I've been loving my Thinkpad E16.

Boot off the live boot disk and, after mounting everything, chroot into your Fedora install. Then try rebuilding your initramfs (I don't know the command for Fedora, but I'm sure it's simple enough).