YARONGTECH Dual Frequentie Beschrijfbare Herschrijven RFID Keyfos 13.56MHZ 1K UID en T5577 125KHZ ID Key Card (Pack van 5) (Blauw)

I have bought and tested these, as I was facinated by the bad reviews about the HF side not being UID changeable.Well, it is fine.there are some catches though, and you will likely need a proxmark to do it.Many cheap chinese cloners probably won't be able to write to these tags.Ok, first to say, the t5577 chip is a genuine one that supports multiple downlinks and test mode, Nice!!!The Mf1k side is a gen2 cuid with gen4 uscuid supposedly as well.It requires direct block 0 write, *not* the chinese magic write.so the cwrite and csetuid commands won't work.This is good, because a lot of access control systems exploit that to discover and break coppied tags.What to do, and it's a bit of faffing, but first make a copy onto a gen1a magic card, and set everything up as you want it.hf mf csetuid -u 11223344This will correctly calculate bcc bytes etc. and so you won't make a brick by getting that wrong!Now read the whole block back and look in the logs and copy it exactly to the folloeing command:place this product on the HF side of the proxmark and do:hf mf wrbl --force --b 0 -d 02003200300804006263646566676869where the stuff after -d is your block to be written.It works!Yes, it's a fiddle for the inexperienced, but it's worth it because it will not be detected as a clone by the majority of building access systems.The flipper0 people are busy hoovering up code from proxmark, and I'm sure they will eventually implament write commands for these.