It's a bit silent here.. let's give this thread a bump. The EEZ H24005 is a great project FWIW and I have build three pieces so far.
@prasimix:
I feel a bit like the sorcerers apprentice digging into this. The possibility to open the psu-firmware project file was not presented and discussed yet, nevertheless..
It all started with trying to correct some typo's in the screen texts. It looked like this could be done using EEZ-Studio after opening the psu.eez-project file. I felt a bit uncertain about what I was doing, but it worked out fine. After correcting some typo's in the texts of the pages just "Build" and "Save". Several files are updated auto-magically... Then start the Arduino environment, compile and load the corrected firmware. Nice!
Next was cleaning up the small text font characters, pixel editing character by character. Same procedure.. Nice!
And then.. the degree symbol. It shows on screen as "oC" while "°C" is intended. Of course this is a "minor" issue, but a device wherein so many hours of development are invested deserves better, I think. For this a simple text correction didn't work, for several different reasons I think. Ascii code page problems, 'char' type signed or unsigned, It proved too difficult for me, I am only apprentice remember..!
So I copied a trick that is used elsewhere in the psu firmware. Also icons are addressed as text item. I created a new icon "°C" at position 151 in the small fonts section of the psu.eez-project file. Most probably you consider this as a definite "NoNo", editing this file by hand. But it worked. After changing the text string in value.cpp from "oC" to "\u0097" the new icon "°C" shows up on the display, after compile and load of course.
I took the liberty to open an issue on Github about this and uploaded the altered files there.
Some pictures of the display "Before" and "After" are posted here to get an idea of the cleaned fonts and the "°C" symbol.
Maybe these alterations can be taken along in the next firmware update.