Incoming wall of text:
I have issues myself with my unit (agb) that has the funnyplaying v2 IPS screen, attempting to take the console out of sleep simply powers the console off. It claims to play just fine with official hardware though. (I'm currently looking to add a legit game with sleep mode to my collection verify this claim). And of course, just to clarify, sleep mode works fine with my everdrive gba on units with official screens and even the gameboy player. The funnyplaying v2 IPS screen allows brightness adjustment (if you solder it into the select, r, and l) by holding select and r to lower it and l to increase it. I'm wondering if the brightness adjustment somehow interferes with sleep mode as it is wired in on the same buttons that trigger the wake function. I'm considering desoldering the cable (it still works without soldering, just with a stuck brightness level of 3, which actually looks fine) to check if that is actually the root causing the interference with the changing of powerlevels during sleep and waking, or if it's the screen itself.
Infact now that I'm thinking about it, the brightness control seems rather.. unstable. I wish I had a way on hand to measure the power levels during play, but I could swear by watching the light that just touching the buttons (select mostly) that the wires are soldered to causes a difference in power draw as the gba light goes from green to red. This is just playing a game mind you, not adjusting brightness. Considering that, it sees a bit unstable.
I suppose I could fiddle with the potentiometer, though I'm not seeing any jitter, with a default screen in some cases you can crank it enough that the unit doesn't want to power on. Given that, perhaps fiddling with the POT adjustment would set the screen power at a level that is compatible with sleep mode.
Another component to consider is the often overlooked batteries. With the SP this is less of a variable, but with the original models most people are probably running on eneloops or another rechargeable that often during use put out around 1.2-1.3ish instead of the expected 1.5v. This typically isn't an issue at all, but when we're dealing with weird powerstates like powering down the screen while leaving the console running, I imagine the wrong batteries could interfere with this process. I certainly wouldn't expect good results from the sunbeam dollar store batteries, most of which aren't even alkaline and are low drain batteries meant for a backup in clocks and the like. I've been wanting to pickup some NiZn (Nickle-Zinc) batteries as they've recently finally hit production for the consumer market and seem like a good alternative. NiZN runs at 1.65, so who knows how that would work, but I really want to find out.
Its your unofficial hardware as I just tried it with minish cap 10 mins in sleep mode on a GBA SP AGS-101 and no problems at all
I agree that it might be a case of unofficial hardware seemingly often conflicting with the everdrive gba x5.
I guess the real question this raises -
Is the everdrive gba handling low power/sleep mode states differently than official hardware would? It seems to be, given these conflicts with aftermarket enhancements and hardware.
As krikzz has updated compatibility with clone devices in the past, I'm holding out hope that his minor issue with different screens will be ironed out with time.
Just hoping he notices it and cares enough about it to respond!
Oh and if anyone (especially krikzz <3) wants information, demonstrations, or a teardown and breakdown of the hardware and issues in question, let me know. I'd be happy to provide whatever is requested to further the communities knowledge on these issues and potentially expand compatibility.
Edit:
[And this might not be the right place to complain but the post verification process is kind of arduous. I get deterring bots, but it really makes it hard to report issues with krikzz hardware when the forum interface is unfriendly.For example, I spent about 25 minutes figuring out how it wanted me to input the processor name. There are many ways you could write it but it's picky about accepting variations. I still can't figure out what to input for the president one, I just have to keep inputting wait till it changes to another question. I feel lucky when a post goes through, it really has to be worth saying to make the effort of posting. But I guess that's kind of the point.]
Edit's edit: Oh the verification went away after a few posts , phew, that was an intimidating hazing ritual, but I guess I'm one of you now.