Kernel Panic When Trying to Upgrade from USB

I still don’t understand why OP doesn’t create his Leap boot USB from 15.5 DVD .iso while booted to 15.1. I just got done booting into the 15.5 installer from an ancient 8G USB stick on a 3.0GHz E8400 Core2Duo HP, which is about 3 or more years older than OP’s Dell. I created the stick logged in as root in 15.5 thus:

# ddrescue --force openSUSE-Leap-15.5-DVD-x86_64-Current.iso /dev/sdg
GNU ddrescue 1.23
Press Ctrl-C to interrupt
     ipos:    4413 MB, non-trimmed:        0 B,  current rate:   5832 kB/s
     opos:    4413 MB, non-scraped:        0 B,  average rate:  72351 kB/s
non-tried:        0 B,  bad-sector:        0 B,    error rate:       0 B/s
  rescued:    4413 MB,   bad areas:        0,        run time:          1m
pct rescued:  100.00%, read errors:        0,  remaining time:         n/a
                              time since last successful read:         n/a

I did basically the same thing when 15.1 was the current Leap. Using this method I feel safe in skipping the sha/md5 steps, and don’t need to guess how far along the process has proceeded while using simply dd.

The only reason is time. I should have time over the weekend to try the ddrescue command. I’ll let you know how it goes. Thank you!