The link above is for a German forum that requires registration to see any links. I've found a direct download of the v3.0.1 firmware, in case anybody is searching for one:
https://mega.nz/file/jUI3SQJa#k_yGLN...gkpdaG1WoYx6mQ
* I haven't tried updating with the firmware yet, so the usual caveats apply, but I found the link in this
article about updating via Linux. It seems legitimate, so I'm fairly happy to trust that the firmware isn't sketchy.