Doesn't work on some GBAs

[SalamencePrince]

My original Supercard SD with old official firmware (v185) never worked on either of my GBA SPs. What happens is after loading a ROM it gets stuck on a white screen. I tested it many times and it never worked. But it worked fine on my Nintendo DS Lite.
At some point I found superfw and tried it hoping it would work on my SPs. Superfw does work on my NDSL just fine. But on both of my SPs any file name listed is gibberish, file sizes are wrong, and nothing loads when selected. I tested it with a friends SP many times and surprisingly it worked fine every time I tested it. It just doesn't work on either of my SPs. I even tried swapping batteries between consoles but nothing changed.
Here you can see my SP on the left and my friend's on the right:

When I started writing this issue I saw the v0.18 update and figured I should test it before posting. Initially while testing the problem seemed to persist. But while testing some features in the firmware to see what works something strange happened. I ran one of the tests, I think it was the SDRAM test, and the system rebooted. All the way back to the GBA bios boot screen. Then the superfw splash showed as usual. And after it finished loading all the file names showed like normal in readable text. I tried booting Pokemon and the game loaded fine and I was able to load my save and play for a while. I tried rebooting the system again to record exactly what I did but this time the SDRAM test showed the normal loading bar instead of rebooting. Next I tried to test the new v0.18 firmware on my second SP and somehow it booted up and worked fine without any issues on the first attempt. I loaded a ROM and played for a while. But after rebooting to test it again it was back to gibberish files which wouldn't load. I have no idea how this happened. After that I tried many times to get it working again without success. I'm not sure what this proves or if it's even helpful. I am aware that this could just be an issue with my SPs hardware which you can't do anything about. But I'm hoping to learn more and maybe find some kind of fix. And I'm curious to know if anyone else has this issue.

[davidgfnet]

If your original firmware did not work correctly... it is most likely a hardware issue. Not much we can do sorry!

[SalamencePrince]

I was afraid so, but it makes sense. Any idea why it did work a couple times with superfw v0.18?
And I have another question. I did skim through the issues before posting to avoid duplicate issues. But after looking again I am wondering, is this issue is related to #6? My SPs are AGS-CPU-01 and AGS-CPU-21 and my friend's SP which works with the firmware is AGS-CPU-30.

[davidgfnet]

Check out gbatemp or similar forums. Some devices just dont really work well. I also suspect the carts themselves, since others do work. Could be a quality issue, some assembly issues (i.e resistor values are slightly wrong or something), etc. It is clear that the different devices have slightly different bus timings/impedances.

[SalamencePrince]

Alright, thank you. It sounds like whatever the issue is it probably can't be compensated for in the firmware. I'll take a look at the forums to see what I can learn. Maybe I can mod my supercard to make it work.

[Buzbee]

Your internal battery is dead. You need to unsolder the old battery and resolder a new one. Easier to just buy a new supercard.

[davidgfnet]

Hey folks
I'm told this could be an issue with the PCB revision of the GBA, not the SoC.
It would be very useful if anyone having these issues could write their Hardware info, so we can spot a pattern. Of course this is only in case your SC works great on other devices but that one. SC might fail for many other reasons, so ensure you test it on a SP / NDS and it works flawlessly there.

Here there's a HW database: https://gbhwdb.gekkio.fi/consoles/agb/

If you can dump the CPU version great, but most importantly the PCB revision. This is a number that's visible without having to disassemble the device, through the battery hole:

[sudsharescraping]

i have tested both ver 0.18 and 0.19 but most games does not boot on AGB-CPU-02 even with fastboot disabled
i have also tested with the orignal firmware of supercard ver 1.85 on AGB-CPU-02 and there games boot without any issue only save state doesnot work
i have also tested after recaping the AGB-CPU-02 console and over volting upto 3.7 volts but the issue was still there
i have also tested all three firmwares on the same supercard on gba sp 001, gba sp 101, gba micro, nds phat and nds lite which works flawlessly

[angiulo]

I recently purchased a Supercard for my modded GBA SP (AGS-001). I was very excited to be able to play all of my games with one GBA cart but when I booted the SP with the card inserted, It didn't work. I would get a white screen. I went down a few internet rabbit holes and Youtube videos to try to get this to work. After reading the comments section in one of the videos I watched (https://www.youtube.com/watch?v=nzzFrSbHfaU), someone said to boot the GBA, remove and reinsert the cart and it will reload correctly. To my amazement, it worked! I was able to flash SuperFW and start playing. Anytime I want to play, I just have to reinsert the cart after turning on the SP. When I see the gibberish text, I just remove the cart with the SP still on and reinsure and it load perfectly fine. Not sure why this happens but I am glad there is a workaround. Sorry if this is known issue and "solution" thought I could help someone.

[SalamencePrince]

I'm surprised that workaround actually works! That explains why when my system randomly rebooted it started working. Maybe the cart was loose and I bumped it.
Someone mentioned that I should replace the battery in my SuperCard, I already tried that and the issue seems to persist. Also, with a fresh battery the RTC doesn't seem to work.

Here are the systems I tested with the supercard. I have no idea how to find the PCB revision on an AGS. I tried googling it but nobody seems to even know what a PCB revision is.
AGS-001 with AGS-CPU-30 (Works with SuperCard)
AGS-001 with AGS-CPU-01 (Doesn't work)
AGS-001 with AGS-CPU-21 (Doesn't work)
USG-001 with USG-CPU-01 (Works)