Everdrive not playing some ROMs

[grache]

On two different systems (a TG-16 and a PCE) my Everdrive won't play certain ROMs. One of them is Cadash. I've tried three different copies, all three of them and the file on the SD card have the same md5sum: cb73d8b307801282d0b6f0a1ed65ae3c

I'm going to get another SD card to see if the problem lies there.

[majors]

I had issues with the US Cadash on an older flash card. Does the JP ROM run? I figured my issue was I was running on a JP system, and the flash card had a loading utility that would switch region of the ROM.

[grache]

I had issues with the US Cadash on an older flash card. Does the JP ROM run? I figured my issue was I was running on a JP system, and the flash card had a loading utility that would switch region of the ROM.

Yeah I tried the JP version and it works. I've tested on both PCE and TG-16. I know the US version of Cadash works for others.

Which flashcard were you using?

[majors]

Tototek 32m flash card. I've since lost it, so I'm looking to upgrade to the EverDrive soon.

[grache]

A little follow up in case anyone in the future has similar problems.

I tested with another SD card, and also on a PCE Duo. The same issues persists. Also, some games, Batman and SFII being examples, will load and play the intro music but not output any graphics.

I contacted Krikzz and I'm sending it in for repairs. I'm curious to find out what's causing these problems and will report back here.

[SamIAm]

Are you using the No-Intro romset? That one seems to be the best bet for most games.

Just last night, I loaded up Batman on my Everdrive and played the first several sub-stages with no trouble. I'll try to get the checksum for you later, but it was from the No-Intro set.

PCE roms are somewhat cursed. While games from other consoles usually have a checksum in the ROM itself that makes it easy to confirm a good dump, PCE games do not, and it's likely that there are a number of bad dumps out there. I really hope that someday, there is a community effort to dump and cross check each game with multiple copies and dumpers.

[Gentlegamer]

Are you using the No-Intro romset? That one seems to be the best bet for most games.

Just last night, I loaded up Batman on my Everdrive and played the first several sub-stages with no trouble. I'll try to get the checksum for you later, but it was from the No-Intro set.

PCE roms are somewhat cursed. While games from other consoles usually have a checksum in the ROM itself that makes it easy to confirm a good dump, PCE games do not, and it's likely that there are a number of bad dumps out there. I really hope that someday, there is a community effort to dump and cross check each game with multiple copies and dumpers.

I think the Ootake emulator checks the ROM and can repair it if it has wrong checksum.

[SamIAm]

Well, a corrupt ROM is basically unfixable. The problem with PCE ROMs is that there is no way to test if a dumped ROM has any corruption in the first place. SNES and Genesis games have their checksums programmed into the games themselves, but PCE games don't.

If it's a problem with headers and/or interleaving, then that's something an emulator might deal with well. It's also what trips up a lot of PCE romsets when trying to run them on an everdrive.

[ishiyakazuo]

The Cadash ROM in the GoodSet has the wrong endian.  It was obviously ripped on a PCE copier.  Need to run it through a tool that flips the bits around.

[Bernie]

Anyone with issues running roms on the EverDrive, just PM me.

[grache]

Thanks to SamIAm I have a working version of Cadash, Batman and SFII. It appears that a non working version of Cadash is in at least 3 different ROM sets.

The Cadash ROM in the GoodSet has the wrong endian.  It was obviously ripped on a PCE copier.  Need to run it through a tool that flips the bits around.

So the PCE is big endian and the TG16 little endian (or vice versa)? I'd have thought that they were the same endianess with the cartidge pins routed differently. I guess that flip of pins flips the endianess?

Anyone with issues running roms on the EverDrive, just PM me. 

PM sent, thanks.

[ishiyakazuo]

The Cadash ROM in the GoodSet has the wrong endian.  It was obviously ripped on a PCE copier.  Need to run it through a tool that flips the bits around.

So the PCE is big endian and the TG16 little endian (or vice versa)? I'd have thought that they were the same endianess with the cartidge pins routed differently. I guess that flip of pins flips the endianess?

It's not big vs. little endianness, but "bit endianness" that I was referring to.  One goes D7-D0, the other goes D0-D7.  Order is completely flipped.  If you rip a TG16 card with a PCE copier (or vice-versa), the bits in the resulting ROM will all be flipped.  There were about half a dozen ROMs in the GoodSet that exhibited that.  Since bit endianness in ROM files is fixed (regardless of whether or not it's PCE or TG16, there is a single way that makes sense on a PC), these ROMs are bad and need to be flipped back to the correct order in order to work.

[pdiggitydogg]

I never thought about this... I have a bad version of Cadash, too, and always wondered why it (and a couple others) didnt load for me.

[munchiaz]

good info all around.

[synbiosfan]

Anyone with issues running roms on the EverDrive, just PM me.

A thousand times this!

No issues

[graffias79]

If the bit endian is wrong and this is the difference between PCE and TG-16 cards, does flipping the Everdrive's region switch to the opposite position make it work?

[ishiyakazuo]

If the bit endian is wrong and this is the difference between PCE and TG-16 cards, does flipping the Everdrive's region switch to the opposite position make it work?

Well... here's the thing with that.  The Everdrive has to provide a menu to load the ROM, right?  That needs to be in the correct bit ordering to play on the particular console.  Maybe it will work if there's a way to also reset the PCE (without resetting the Everdrive) and flipping the switch.
Easier thing is to use a tool to flip the bits around.  I think the Flash HuCard GUI can do it.

[graffias79]

Good point.  So theoretically yes but not a quick and dirty solution.