the later lot of ak2s had a File Allocation Table error. the error comes down to a poor solder job on certain kits. i can't pull an exact date anymore but i think it started around june/july of last summer. the kits do a bunch of things from freezing on boot up with the text "FAT ERROR", to flashing, to glitches, to other problems. all of the issues cause the card to not work. acekard does have a 1yr warranty and it is well known that this problem exists. this doesn't mean you have this problem. i know people with the early batch who still use them all the time. the fat error was later *fixed* and rebranded as the ak2.1. this one has a green pcb and the small chip just under the sticker. the pcb was later redesigned and released as the 2.1 black pcb and then a run in a forest green color. the newest version is the ak2.1 with a blue pcb.