Booting from USB drive.. not port agnostic

I have installed Leap 42.1 (and upgraded to 42.2) on a USB drive. It works fine but occasionally, the system does not boot. When it happens, I just have to switch the USB drive to another port (usually to the port that I used when installing the first time).

On Leap 42.1, the booting hung at:

OK ] Stareted Show Plymouth Bot Screen.
OK ] Reached target Paths.
OK ] Reached target Basic System.

Now, on Leap 42.2 it hangs at the same time but without the above output.

Here my boot log: http://pastebin.com/FXtRjGpn

At one time, I had that problem with one computer. I’m pretty sure that it was a BIOS problem.

Well, it seems to be the best explanation that I can get, right? It is not very satisfactory to not have any way to fix it. Is there no further diagnosis to do in order to find the potential root cause? I assume that live images do not show this kind of behavior.

That would be a problem with the BIOS in the computer, nothing to do with openSUSE. I have seen similar problems in various laptops. In one case – an Acer – re-installing the BIOS firmware, same version, would fix it for awhile, then it would act up again sometime down the road. Really annoying, and worrisome, since burning the BIOS over and over again is not a safe thing to have to do.

OK, thanks for the explanation.

For your information, here is my boot log: https://paste.opensuse.org/57090458
The turning point happens on line 1010 when I plug my USB drive into another port and it gets recognized, assigned to sdb2 and the system boots (line 1029 is the next verbose output).