PANIC: replication checkpoint has wrong magic 0 instead of …??

Dear community,

after a hardware failure, I get (with PostgreSQL 11.2) output at starting;
the partition itself appears to be clean:

2020-07-19 13:08:14.825 GMT [2410] LOG: listening on IPv4 address
"127.0.0.1", port 5432
2020-07-19 13:08:14.838 GMT [2410] LOG: listening on Unix socket
"/tmp/.s.PGSQL.5432"
2020-07-19 13:08:15.041 GMT [2411] LOG: database system was shut down at
2020-07-06 08:05:05 GMT
2020-07-19 13:08:15.045 GMT [2411] PANIC: replication checkpoint has wrong
magic 0 instead of 307747550
2020-07-19 13:08:15.187 GMT [2410] LOG: startup process (PID 2411) was
terminated by signal 6: Aborted
2020-07-19 13:08:15.187 GMT [2410] LOG: aborting startup due to startup
process failure
2020-07-19 13:08:15.188 GMT [2410] LOG: database system is shut down

A web search wasn't too verbose about this.

Any ideas? Can this be fixed somehow?

Thanks a lot in advance, Nick