HP50g - Can't Factory Reset & What's this?

[BartDB]

Hi,

The splash screen you are seeing the the MetaKernel. It was an add-on for the 48-series, but is included as part of the ROM in the 50g.

https://www.hpcalc.org/hp48/apps/mk/mk.php

You have 2.09 and might want to upgrade to 2.15
https://www.hpcalc.org/details/7097

Note that none of the resets will delete the flash memory (port 2). Any programs and libraries installed there will remain after resets. You would have to delete it manually.

However, the Equation Library and Periodic table are also stored there. These can be recovered though (they're included in the zip file with ROM 2.15).

So a "factory" HP-50g would have been reset with ON-F1-F6 with 'NO' to "recover memory?" and the following in the Flash:
PRTBL: Periodic Table L229
EQLIB: Equation Lib L227
EQLIB: Equation Data L226

Edit:
To see the internal serial number, type (in RPN mode):
256 ATTACH [Enter]
SERIAL [Enter]

NOTE: this is not the same as the external serial number (missing in your case).

-B