The OSD font could not be loaded
What ArduPilot says:
- OSD: Failed to load font N
- AP_OSD: bad font size N
The analog OSD chip needs a font file to draw its symbols. ArduPilot looks for font0.bin (the digit is OSD_FONT) on the SD card first, then among the fonts built into the firmware. “Failed to load font” means it found neither, and it then falls back to font 0. “bad font size” means a file was found but is not 13824 bytes long, so it is not a font for this chip. Symbols may be missing or wrong on the screen.
What to do, most likely first
OSD_FONTnames a font this firmware does not carry (small boards include only one or two).FixSet
OSD_FONTto 0, or copy the font file you want from ArduPilot's fonts to the SD card's top folder under the name the message asks for.A font file on the SD card is damaged or made for another OSD.
CheckLook for font0.bin to font9.bin in the card's top folder and compare the size with 13824 bytes.
FixDelete it or replace it with a proper font file.
Parameters to look at
| Parameter | What it is |
|---|---|
OSD_FONT | OSD Font |
OSD_TYPE | OSD type |
Where to do it:Firmware Inspector
The code that sends it
OSD: Failed to load font N
libraries/AP_OSD/AP_OSD_Backend.cpp AP_OSD_Backend::load_font_data() · Open in ArduPilot Copter-4.7.1
AP_OSD: bad font size N
libraries/AP_OSD/AP_OSD_MAX7456.cpp AP_OSD_MAX7456::update_font() · Open in ArduPilot Copter-4.7.1