HP 75 Expansion Pod

[Michael Fehlhammer]

Recently I acquired an HP 75 expansion pod that exhibits strange behaviour:
After a reset ( INITIALIZE ) of the electronic disk, XMEM shows only 24436 Bytes available. I know there are two versions of expansion pods, featuring 32K and 64K of electronic disk space, respectively. But 24K ??
There is not much file system overhead, a 64K pod shows 65492 Bytes free when executing XMEM.
Serial number is 2419A00008. Maybe a prototype?
Or is the memory organized in 4 banks, and one might be damaged?

Is it possible to upgrade a 32K pod to a 64K pod ( or even larger ) easily?