i didn't have the same board as you, but i was able to make it work at 5.2v.
The Step-Down Converter ,wich is a JW5022 (datasheet here) output 5v on pin 3 (see datasheet), so by putting 5v directly on this pin it will work like a charm ( maybe i can take of the chip too ?)
the board itself (i don't think i have seen it in the topic ?)
the JW5022 Synchronous Step-Down Converter (sorry i took the picture after the mod so we can't really see the name)
The screen working with a Pi zero w, both on a gba sp battery. (850mha, maybe a little bit low )
i thought this might help someone ^^
I have the same screen as this. I found another link online that shows this chip removed. Have you tried it?
http://www.sudomod.com/wiki/index.php?t ... #Variant_9
Also can the set of three buttons be removed from the screen if only one AV source is being used? Should the board detect which AV line is in use?