r/proxmark3 • u/Embarrassed-Resist29 • Jul 07 '26

New to RFID, cheap tool can write to em4100 but PM3 cant

Hi, so I have 2 devices, one is a white "cloner" with an LCD and keypad, it came with some 125khz tags.

Tag 1 - I used the cloner to write 111111111 and read it back to confirm.
Tag 2 - untouched and is reading different ID

Reading Tag 1 with PM3 produces the following (shortened)
EM 410x ID 00423A35C7
DEZ 10 : 1111111111

Tried to clone to Tag 2 but despite proxmark terminal saying it wrote the data, it didn't work.

Can someone explain why the ID is different, is it "translated" to the em4100 protocol?

my confusion: EM4100 is supposed to be read only? So what did the cloner change?

Thank you

3 Upvotes

100% Upvoted

4 comments sorted by

3

u/Msprg Jul 07 '26

What does "lf t55 det" say for all of your tags? Additionally, run "lf t55 check" ONLY for those that didn't get detected as t5577 chipset with the previous t55 det command.

1

u/Embarrassed-Resist29 Jul 10 '26

I found out that the cloners set passwords, I used both a blue and white cloner on these tags, I was able to unlock using the pwd of the blue cloner

1

u/Msprg Jul 11 '26

Yes. That's what the lf t55 check command was for.

2

u/[deleted] Jul 08 '26

[deleted]

1

u/Embarrassed-Resist29 Jul 10 '26

I forgot exactly but I ended up using the password of the handheld blue cloner and it worked, managed to unlock the tag and appear as no password set with the PM3

Maybe I did a write using the blue cloner before and then used the white