While thinking about the calibration wizard, the idea occurred to me, that empty EEPROM-space may be used to store user data. For example the calibration date. So I added read and write functions for whole addresses, to see if it works.
It does work with unused EEPROM-Space, for example register 0x0F bits 20-23. Other unused bits may be used as well. They can be accessed by using the writeEEPROMValue function, with a 32-bit mask, where the corresponding bit-positions are 0.
For long-term datalogging, an SD card can be used. Because the space is somewhat limited, for such a bulky SD card, a 6-pin header was added. The SD-card can be mounted anywhere in the housing and connected to them, just like the display. And I added pin-descriptions, because I they were missing.