Hullo hullo
Bought some tags recently - the 2 screenshots are 2 different transactions, from the same listing. Confused as to whether the latest purchase (the Gen2 & 4) is capable of both, or if i will on;y be able to write once, and how to navigate this
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The first one appears to be FUID, the second one a USCUID
FUID is a sub-type of USCUID, which is a type of Gen4 known as GDM. Generally, when people talk about “Gen4” they mean the UMC Gen4 GTU though, which is a little more powerful
You can learn a little more about them with the hf mf gdmcfg command
Gen4 chips (GDM and GTU) have the option to enable Gen2 direct write for block 0, so it’s not weird to see one tag report both magic capabilities. This can usually be toggled on and off if you want/need.
From the FUID info link:
Known as “write only once”, which is only partially true, because old revisions had backdoor commands enabled, so you could manipulate the tag, using them. Newer FUIDs are based on new implementation of chip and have backdoor commands disabled by default.
Allows direct write to block 0 only when UID is default
AA55C396. If your tag responds to a20(7),23magic wakeup, the UID could always be rewritten multiple times with backdoors commands, but that makes that tag detecteable.
So, you should be able to determine whether or not it’s a true “Write-Once” based on whether it responds to hf mf gdmcfg --gdm
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Have you seen the video on the flexUG4 page? This is demonstrated in terms of configuration and use 
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Thanks people
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