Short version: If you think you did everything right(with linked nand,with valid gba cia,with right rxtools installation) but gba virtual console doesn't work(black screen with white words) in rxmode sysnand or emunand with rxtools2.6/3.0b2 (but maybe work in devmode sysnand). (note1: rxtools2.6 is said to be support gba without patched gba_firm . note2: devmode is available in 3.0b2 but not in 2.6 ) Try to do as below: 0. install FBI in sysnand 1. run FBI,use L R button to change mode to "delete title" and destination to "nand",delete 0004013800000202 if there exists one.(it's safe.but if you delete wrong thing,this may brick your console.) 2. install patched 0004013800000202.cia(for my oldJPN console,crc32 is 5609403D) in your sysnand (not emunand） to destination "nand"(not "sdcard") 3. delete folder "data" and "nand" in sdcard:\\rxTools. 4. reboot into rxtools.Rxtools will reinstall,you will see the process. Then your gba virtual console will likely work in both sysnand and emunand. Longer version: My console is JPN 4.5 with emunand 9.8. I tried rxtools2.6 and 3.0b2. I think I did everything right but Gba virtual console doesnt work in rxmode sysnand or emunand. I searched on Google and find some suggests.I have tried to format my console,tried emu nand 4.5,tried install gba on both sysnand and emu nand,tried install patched gba_firm(though it's said 2.6 and 3.0b2 dont need it to work).nothing helps.It always leads to a black screen on the bottom with white words. When I did the steps above problem solved. I have formatted my sysnand and recreated emunand several times to do some test and I am pretty sure problem exists before these steps and dispears after these steps on my console. I guess i found the reason. When install rxtools2.6 and 3.0b2 first time,it search gba_firm(0004013800000202) in sysnand(only sysnand,not emunand) and patch it to created 0004013800000202.bin in sdcard:rxtools/data.After installation,rxtool 2.6/3.0b2 doesnt used 0004013800000202 in sysnand or emunand any more,it use 0004013800000202.bin instead. But there exist some gba_firm versions which unexpected in rxtool 2.6/3.0b2 ,this lead to bad 0004013800000202.bin. Problem exists even though you install right version of gba_firm in sysnand or emunand,because of rxtools doesnt recreate 0004013800000202.bin. You must delete folder in rxTools to make rxtools reinstall to create new 0004013800000202.bin . It also works if i manual replace the bad 0004013800000202.bin with a right one(copy from the one when gba virtual console work) .So it is clear the reason is bad 0004013800000202.bin. If you used rxtools with version smaller than 2.6 to play gba virtual console successfully before,you will unlikely meet this problem after update becaused rxtools 2.6/3.0b2 can handle a patched gba_frim (i guess). It cost me a whole day to make gba work and half a day to find out how it works.I just want to save others' time,pardon me if i was wrong or I wasted your time. UPDATE1: I have download one unpatched v3665 gba_firm(crc E178FDA9).It runs ok with these steps(and with the unpatched v3665 one,Rxtools generate same 0004013800000202.bin with crc32 418869EC as the patched one). So the problem is more clear.Rxtools works well with both patched or unpatched v3665 gba_firm.But not with the original gba_firm comes with my old4.5JP console. There is a simple solution.We can just add suggestion to document to suggest user with old 3DS console to replace their gba_firm in sysnand with a patched or unpatched v3665 one to make sure gba virtual console game work.And tell user to let rxtools regenerate 0004013800000202.bin if they replace gba_firm after the installation of rxtool2.6/3.02b.