Try getting the proxmark3 to detect what type of chip it is. The csetuid command is for gen1a chips only. They might be gen2 chips, for example, which just use the standard write command to change sector 0 (where the UID lives).
Run hf search or hf mf info to start.
I just realized you are talking about 15693.. so csetuid is not even for the correct ISO standard. Specifically, csetuid is for gen1a Magic Mifare 1K chips which are ISO14443A chips, not ISO15693.
To work with ISO15693 changeable UID chips, there is a LUA script you can try;
I tried using csetuid within the hf 15 menu, which I thought would be the way to change it, however the script didn’t work either, as shown in the screenshot.
Can you explain the -hack options in the hf 15 command?
From what I understand, two commands are needed, each with 4 bytes of the uid. I might need to use one of these options to keep the tag active, but I don’t know which one.
I specifically requested chips with a 28mm diameter, ISO15693 protocol, ICODE SLIX tags with changeable UID.
With 1k bits of memory.
At the time of sale, he mentioned that the PM3 wouldn’t be able to modify it, but I think he only resells the chip and doesn’t have information on how to proceed with modifying it using the PM3.