I’m sharing a working SWEREF17_RH2000 geoid file for Sweden, prepared using data from the official Lantmäteriet source:

https://www.lantmateriet.se/sv/geodata/gps-geodesi-och-swepos/Transformationer/Geoidmodeller/
 

None of the available formats worked correctly in SurPad 4.2: the file could be loaded, but it had no effect on the displayed heights.
 

To resolve this, the data was processed through the following workflow:
 

Web → QGIS → Trimble GRID Factory → Trimble Business Center
 

The resulting geoid file applies height corrections correctly in SurPad 4.2.
 

You can download it here:
https://surpadapp.com/community/geoid/sweden/sw172000.ggf