See this one for instructions how to dump a memory location using debug:

http://mess.redump.net/dumping/dump_bios_using_debug

The logo should be in the 8K block between ED000h and EDFFFh

Perhaps there are some more friendly tools that can dump stuff from arbitrary location. But I'd need to spin up my PC to find one...

SheikYerbouti wrote on 2020-06-02, 09:20:

Also how can you restore it after the BIOS update, if the update removes the splash screen?

putting your .usr file back with the same tooling after flashing the bios.