A lot of the copy protection issues on DS were made much worse on DSi and later... You can run fake (bootlegged/unsigned) games on DS and DS lite pretty easily... DSi added region locking, and became sensitive to any slight differences in the product. So even older games that weren't necessarily 'copy protected' would throw the security algorithms on DSI and 3DSs. They kept updating the firmware on those too, to find more 'fakes'.
I wouldn't be surprised if the region/security measures are very much linked together actually.
Thanks for the explanation and link. The reason I rather want to launch DSi game from their native environment is because that's what they are designed to do, and in case there is a problem from launching them from a flashcart. Having both options woudn't be bad though, but I really dislike unnecessary patching, cracking and meddling in software in general.
The problem is if you soft mod your system you risk even worse things... With moded/hacked roms you can turn system off, and turning it on usually resets teh system back to its standard settings as nothing is modified on the system itself.
But soft modding opens up possibilities of screwing the operating system up or permanently bricking it. So in that situation the whole 'loading' a game into DSI's memory (which is tied heavily into the security/operating system) might actually be worse 'hacking' than hacking the files themselves to run as regular roms. Besides those files generally still have to be 'decrypted' modified in the first place to get past that security. So they will be 'patched' in some form.... No way to get past that really...
If the DS flashcart supports linking a GBA rom that you provide on the SD card, you can play the game on the GBA Everdrive, then copy the rom and save file to the DS flashcart to link. My old M3 Lite and the DSTWO both supported GBA/DS linking of roms, but both seemed problematic. The M3 had an option in the patcher (which was done externally on the PC via a manager) but it only seemed to work with some supported games, which wasn't very many. The DSTWO has an option in the settings "GBA Extend" which should allow you to select a GBA rom and save file for linking. But people seems to have trouble getting it to work (I haven't tried it myself yet).
If your goal is just to transfer pokemon, people suggest to do it in an emulator that supports GBA/DS linkage, like DeSmume, instead. But for games that adds extra features only when a specific GBA game is in slot-2, you may be out of luck.
So this is also a desired feature of a DS flashcart.
My old M3 Lite was a slot-2 device (a GBA cartridge) as it doubled as a GBA flashcart and also contained an RTC for GBA games that needed that. For that reason though, it didn't support rumble paks which are inserted into slot-2.
I think the difference was early on when DS Lite was largest target, and there was a GBA slot, a lot of the flashcart companies created systems that were designed to function with an 'add-on' GBA card. In fact many of the games kept most of the DS games saved to the GBA card, and mostly used the DS card itself to communicate and load DS games into memory. A lot of these systems had something called "NOR' memory, a non-volatile flash memory that could hold at least one GBA game in memory. Depending on the 'daughter card' if you used that to store a GBA game, you didn't need to have the DS card, in order to use the daughter card in the system, and you could even put the GBA daughter card into a regular GBA and run the game. Now this meant the 'header' was in the primary memory. There was no menu, except for when it was paired with the DS flashcart itself. It would boot to the NOR before it tried to do anything else.
DSTWO lines were generally compatible with most of the daughter card out there. The ones that had NOR feature.
The EZ-Flash 3-1 had that NOR feature as well, just l ike the M3 Perfect.
The benefit to this was that real DS games, and even DS flash carts assuming they were programed t allow the game link, could access that NOR to read 'headers' and be tricked into thinking it was an actual copy of the game, and unlock those extras.
This of course doesn't work for any game that 'looked' at the save file itself, and checked for certain kinds of memory. If a game was converted to save under a different format, the game just couldn't access the memory it was looking for, and thus couldn't unlock the linking abilities. Maybe the games could be 'patched' to look at an alternate kind of memory or some kind of bridge to connect two kinds of games by other means. But unfortunately, Krikkz never included that possibility in his cards.
While there is that new EZ-Flash Omega that has most of the features of Everdrive GBA X5 (including some of its own features like 'save states'), and has a "NOR" apparently it uses the NOR in a very different way... There is no way to directly load to it, and the system will always load to a main menu instead. So thus defeating any chance of access the 'game link' on that flashcard.
DSTWO Plus definitely has features to extend and link to 'real cards' or the tremor pak. But unless I have one of those specific daughter cards, there is no way to link to a flashcart. The Everdrive GBA certainly can't pass that data through to the flashcart, neither can the current EZ-Flash GBA cards.
THere was a larger discussion on what worked and didn't here;
http://krikzz.com/forum/index.php?topic=5842.msg45864#msg45864
