So your EZflash 3in1 doesn't work, eh? Read from top to bottom. Don't miss a section.
Possibly its a dead cart. First, test if the rumble works. Use game like MOON, METROID, HOTEL DUSK ROOM 215 and SUPER PRINCESS PEACH. (enable rumble in acekard setting first. Set it to "Low")
If its not rumble,
1- Its a dead cart.
2- Maybe its your firmware. Upgrade now.
If the rumble works but DS and Acekard wont show them:
1- Its a dead cart. Throw it away. Future NDS games dont support rumble anyway.
2- It wont show until you put something in it (GBA games). use GBA_ExpLoader or Cory's GBALdr. Load it in NOR. Turn off. Pull out slot1 cart. Turn ON.
If GBA game start:
1- Good. Enjoy.
If GBA game stuck at Gameboy screen. (or no GBA screen at all)
1- Its a dead cart. Throw it now.
2- Wait, maybe the way you load the game is wrong. You have to patched the GBA game first. Use GBATA or EZClient. Patch it now and load it again.
The GBA start.
1- Good. Your 3in1 is fully working. You can also use browser now. To save GBA game, put in the slot1 cart, start the GBA from there (from the GBAloader or Acekard), after playing and save, turn off and start again (if you start from gbaloader, open the gbaloader to keep the save. If you start from Acekard, it will save your game automaticly after reboot).
You can only put 1 GBA game in NOR at a time. Some said you can put more than 1, only EZflash V slot1 cart can do that, but since 3in1 only have 64MB NOR memory (new hardware, blue board, older green board have 32MB) not many games can be loaded.
Minimum GBA game size is 8MB (super suck games) and max is 32MB. This multi-rom can't be started in DS firmware, you can only start them in the EZflash V firmware.
GBA wont start.
1- Really, throw it away now. Buy a new one.
I also have a dead cart. EZ 3in1 ALWAYS have a dead cart. Only the lucky one will get the fully working cart. Usually on the second buy. (they're rip-off!!)
Yes, this guide also works with other slot1 cart. Keep the NDS games I mention above. Trust me, they're great games. Other good rumble games are Osu! Tatakae! Ouendan! series (english ver. is Elite Beat Agent, but I dont like the song), Puyo Puyo 15th Anniversary, Mario & Luigi: Partners in Time, Wario: Master in Disguise and Starfox.