Ok , here are the weird findings i have my made : (i own a F2A 256m)
The US version of Zelda doesn't work on my f2a , but the mario version boots. The mario game has sticky buttons , and the keys stop answering after few seconds of play. I duplicated the data , or added 0's to mario for a size of 32m and then mario runs just fine. There seems to be a little shadow behind the text on my SP. I patched the eepromv_124, but mario still won't save. Every other rom ever released , saved fine on my f2a when patched. those 2 don't. If you hold L+R when you boot zelda or mario , you get asked if you want to delete the saved game. if I answer no in zelda , i get the game pak error screen again, if i answer yes it says that the save is corrupted , and then sends me back to the game pak error screen. In mario , if i say yes it says save was deleted and game starts , if no , the game starts also.
In VBA , if you want to do the same , you do this : hold A and S (L + R) and press ctrl + R (Reset) you will now see the message i mentionned "Delete all saved data?" Answer yes , and you get a screen saying that the data was deleted (unlike my f2a) . press B , screen goes black, Now , press L+R again and you will get the game menu , with the choices "Continue" "Reset" "sleep mode" , and from there , if you press reset , the same black screen is shown ,the menu still working. If you choose sleep mode ,some garbage sound comes out , and you can't exit the sleep mode.
With or without the save fix , vba always saves a 8k file, but it should save a 64k file if patched correctly.. so i'm thinking the patcher doesn't patch the rom correctly.. maybe yet another version of v124 ?
My guess is in mario's case , the save isn't critical , its for highscores alone , so the game proceeds over this barrier.. But for zelda , the game needs to save before you can even start playing (right after the name entering screen) so the save being more critical ,it can't proceed if not a valid save is detected (like on my f2a , it tries to delete the save and fails , and goes back to game pak error , but vba achieves erasing the save , and proceeds to trying to load the game , without success).
DreamGBA using a real bios , is yet closer to reality by having stickys keys in zelda , like on some flashcarts , when the size is too small , size fixing it solves that .. (?????????) even with 0's , not only dupe data. Dreamgba also always saves a 64k file.. (it loads if you answer yes when a eeprom_v124 warning screen shows up)
Another weird thing , i have hexedited zelda , jap and us , and the files are very very different . The jap version of zelda , contains about 900k of FF's , and the usa version of zelda is a full 1024k of different data.. And i would think that the Us version would be as small ,or smaller , seeing how it doesn't have japanese text in the name entering screen...
My final guess is this , perhaps these are bad dumps ... or its not really v124 but something just a bit different , (dreamgba 1.4 runs them with crappy colors here , and saves ...) Every other famicom releases worked fine on my f2a , now 1 won't work at all , the other would work , but keys are sticky. 2 that don't work on my f2a are trashman's ... perhaps someone else could dump the carts again , and compare with trashman's..