Comment # 60 on bug 1188896 from Sarah Kriesch

I have installed the debuginfo package (in the past) and extracted the kernel
with:
rpm2cpio kernel-default-*.s390x.rpm | cpio -idmv
Then I was able to use crash with:
crash -c /dev/ttyS0  --cpus 3 boot/vmlinux-*-default.xz s390zl21.memory.dump
(* has to be replaced by the kernel version)

If Rudi has used the referenced method, then it should be possible to open the
dump this way then.
If the dump is from SLE/Leap, you need the kernel download link for SLE 15 SP4
Beta or Leap.