Thanks for the detailed instructions @patbpatb. Worked for me! Out of curiosity, did you try the European Open firmware too? Did it not have Swedish? I have svenska nu i alla fall tack vare till nederlanska firmware so I'm happy
I wonder what the differences are between these firmwares.
I wonder what was up with my phone before. It had an *old* firmware but it had Mango. The firmware was like 188.8.131.52 or something. I bought it on eBay new and unlocked so who knows where it originally came from. Maybe that region had weird updates. Got the Netherlands firmware running now and all is well.