BIOS Freezing After Update On Mega CD

[Farsil]

Hello,

My issue is similar to the one posted some months ago, because I can get to the "space" screen and then the core freezes. If I try to reload the backup RAM, it displays the disc check message, and then it gets stuck on the loading screen forever. This happened after I updated my version from 20230224 to anything newer.

The older core works perfectly fine.

The only other thing that has changed is my SD card, I am using a Samsung EVO Plus 256GB. If that card causes issues, this is the only core that creates that kind of problem, because everything else works perfectly.

Did anyone else have the same issue?

Here is how I arranged my files, for reference:

293471622-118425f7-21c6-4835-90d6-4e898c2a743b.png (74.3 KiB) Viewed 8008 times

[PistolsAtDawn]

SD cards, especially Samsung's, are often counterfeit. Did you get yours through Amazon? They mix their own stock in with their marketplace sellers' stock - which isn't verified. That's how people will sometimes randomly get a fake.

Amazon used to have a specific Samsung Evo Select model that was only made for and sold by Amazon. Those would always be safe, but not the rest.

[gorilladaddy]

Howdy,

I'm new here but I have had a MiSTer about two years now, that I built myself. It is a dual-RAM 256mb set-up. I think I may have a solution for you.

My Sega CD core worked flawlessly up until a couple of weeks ago. It then started to crash almost immediately upon loading the initial BIOS screen(before a game was loaded). It would continue to crash repeatedly, over and over, usually after a few seconds. If it did load a game, the game would inevitably crash back to the BIOS screen and continue to repeatedly crash.

At first I thought it was the recent 12/4/23 update, but I can confirm that was not the cause. I tried several older builds(that had worked flawlessly in the past) and the behavior was the same. I use bin/cue images currently. I tried rearranging directories, chd images, placing the BIOS in the game folder, reinstalling the core completely along with deleting the core's config files, and nothing helped.

I finally opened up my MiSTer to test my SDRAM. I removed both modules and moved switch #4 to single RAM configuration. I then booted up the core with a single module and voila!, the cores worked just fine and booted a bin/cue image without issue. I tried this with the other RAM module and again, no issue. I switched around the original placement of the modules when I put it back together. Tested again, no issue.

I ran the official RAM tester core for a bit to see if any issues were detected with either module, and they were both stable with no errors at 146mHz after 10 minutes. The only thing I can think of is that there may have been a static charge causing the issue that was dissipated when I removed the modules. There have been numerous power outages in my area lately due to winter storms, so maybe it was a ghost in the machine.

Conclusion: My Sega CD core is rock solid again. If my MiSTer exhibits odd, crashy behavior in the future, I will consider replacing my memory modules. The current modules came from Ali Express, but appear to be legit v 2.9 with sorgelig's name on them. This is an issue with your unit and not something sorgelig can fix. I hope this helps somebody.

[FPGA64]

Howdy,

I'm new here but I have had a MiSTer about two years now, that I built myself. It is a dual-RAM 256mb set-up. I think I may have a solution for you.

My Sega CD core worked flawlessly up until a couple of weeks ago. It then started to crash almost immediately upon loading the initial BIOS screen(before a game was loaded). It would continue to crash repeatedly, over and over, usually after a few seconds. If it did load a game, the game would inevitably crash back to the BIOS screen and continue to repeatedly crash.

At first I thought it was the recent 12/4/23 update, but I can confirm that was not the cause. I tried several older builds(that had worked flawlessly in the past) and the behavior was the same. I use bin/cue images currently. I tried rearranging directories, chd images, placing the BIOS in the game folder, reinstalling the core completely along with deleting the core's config files, and nothing helped.

I finally opened up my MiSTer to test my SDRAM. I removed both modules and moved switch #4 to single RAM configuration. I then booted up the core with a single module and voila!, the cores worked just fine and booted a bin/cue image without issue. I tried this with the other RAM module and again, no issue. I switched around the original placement of the modules when I put it back together. Tested again, no issue.

I ran the official RAM tester core for a bit to see if any issues were detected with either module, and they were both stable with no errors at 146mHz after 10 minutes. The only thing I can think of is that there may have been a static charge causing the issue that was dissipated when I removed the modules. There have been numerous power outages in my area lately due to winter storms, so maybe it was a ghost in the machine.

Conclusion: My Sega CD core is rock solid again. If my MiSTer exhibits odd, crashy behavior in the future, I will consider replacing my memory modules. The current modules came from Ali Express, but appear to be legit v 2.9 with sorgelig's name on them. This is an issue with your unit and not something sorgelig can fix. I hope this helps somebody.

Sorgs name is on the PCB design files. It does not mean its approved or of any quality. Especially when found on an ALi Express site. It just shows they downloaded the open source design.

[Farsil]

I did try to test my RAM modules but there were no defects. After all, it was working flawlessly with the previous SD card so there was no reason it would fail now.

I originally fixed the problem by rolling back to a previous version of the core, 20230224, which confirmed at least that the issue wasn't the SD card either.

However, after update 20240408 I cannot reproduce the issue anymore. Not sure what may have caused it, but the problem is no more for me. Hopefully it's the same for everyone else!

[Slychocobo]

Just to add onto this slightly old thread, but I ended up here having experiencing the same issues as above on my new MiSTer setup. Exact same symtoms using the 20240408 core.

However in my case it seems that the core version of Mister I was using was quite out of date by almost a year (despite grabbing the 'Mister_Fusion' pack at the time of posting) and even running update.sh

I ended up having to manually update the Mister version (by the instructions in the bible) and it fixed the issue!

[iamTeddyNL]

The only thing I can think of is that there may have been a static charge causing the issue that was dissipated when I removed the modules. There have been numerous power outages in my area lately due to winter storms, so maybe it was a ghost in the machine.

Unlikely, that's not how static works. Static is a real threat to custom builds, latent damage will decrease life expectancy significantly, and a big zap is instadeath. It would not explain something like you are describing. It might have been a connection failure between the motherboard and the sdram module, which can fix itself simply by plugging it in again.