I purchased two xEM tags in hopes of encoding them with different data using the Proxmark tool. My goal is to use the tags externally (no plans to inject them into the body).
After removing the first tag from the syringe, it showed up as an EM4X tag when doing ‘lf search’ on the Proxmark. ‘lf hid clone …’ would not change the data on the tag. After wiping the tag, ‘lf search’ does not find anything, and I cannot talk to it anymore (even with ‘lf t55xx detect’).
I then tried programming the second tag while still inside of the syringe and sealed polymer bag. ‘lf t55xx detect’ returned results, and I could clone it with ‘lf hid clone …’. Successful cloning was verified by doing an ‘lf search’, and it returned positive results.
However, upon removing the tag from the syringe and placing it close to the antenna (the same angle/direction as when it was still in the bag/syringe), it no longer reads:
proxmark3> lf search
Reading 30000 bytes from device memory
Samples @ 8 bits/smpl, decimation 1:1
NOTE: some demods output possible binary
if it finds something that looks like a tag
False Positives ARE possible
Checking for known tags:
No Known Tags Found!
So now both tags are not returning results. Any help would be appreciated.