I found the way to switch the language!
Hold both arrow buttons down, turn on the station, count 2 seconds, then quickly release the buttons and hold OK until the screen shows up.
FYI, the screen uses the same command set as a PCF8814.
I also found the logo locations and format! There're two of them (For each language).
They can be found by searching these patterns (Use HxD):
English:
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 20 E0 E0 20 E0 E0 20 E0
Chinese:
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 A0 A0 20 20 20
Note down the offsets where the pattern starts.
Make a 128x64 monochrome BMP in Paint or whatever, then upload it here:
https://javl.github.io/image2cpp/- Tick "Invert image colors".
- Draw mode: "Vertical - 1bit per pixel".
- Click "Download as binary".
You should get a file sized exactly 1KB.
Open it in HxD, copy everything, open the fw file, go to the offset position, right-click over it and press Control+B (Paste writing).
Save and flash!