Hi, quite new to this forum. I changed the card type for my FlexUG4 to MiFlare Classic 1k 4 byte. I managed to do a 1:1 clone to it with UID + all the sectors. It worked for me door but it doesn’t work for the elevator.
How do I know if its a range issue or the elevator reader can’t detect the Gen4 card, if i get a FlexM1 v2 will it work or there is no difference between the 2 flex?
I used a china cloner to clone the MiFlare Classic 1k to the FlexUG4 it doesn’t work, only a proxmark3. So I was thinking if this this is the same issue with the elevator where it can only detect a normal MiFlare Classic 1k where it is not a Gen 4 emulated one.
Regards,
SL
Probably it’s a coupling issue
Did your Proxmark come with a Mifare Classic test card?
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I have a miflare classic test card gen1a, i cloned to that and it worked. not sure if the generation matters.
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Not really, and especially not in that direction
Nothing is going to detect a Gen4 but not a Gen1
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you are right, asked claude code. Do you know if the flexm1 antenna is better than the flexug4 in this case? i doubt xmagic xseries will work. Maybe dUG4T might work since the antenna area is wider.
The FlexUG4’s flex antenna is a weak energy harvester. These keypad locks (and many battery-powered readers) don’t run the RF field at full power all the time — to save battery they sit in a low-power standby poll, sending short, weak field pulses. Two things follow:
- A genuine/Gen1a card has an efficient antenna, so it can scrape enough energy out of even that weak standby pulse to power up and reply → single tap opens it.
- The FlexUG4’s thin flex antenna can’t harvest enough from the weak standby pulse. So you tap the keypad first, which fully wakes the lock and turns the RF field on at full power — now the flex card gets enough energy to boot and respond → tap works.
So it was never a data, key, config, or magic-detection problem. It’s purely coupling efficiency: the flex card needs a strong, fully-on field to power up. Strong field (woken door reader) = works. Weak field (standby poll, or a weakly-tuned/recessed elevator reader) = card never powers up = nothing happens.
That also explains the elevator perfectly: the elevator reader is probably running a continuously weak field with no keypad to force it to full power, so the flex card can never harvest enough to reply. The Gen1a, with its better antenna, manages on the weak field — which is why it opens the elevator.
Bottom line:
- Flex antenna = weak power pickup. Works only on strong/fully-awake fields.
- Fixes: use the Gen1a (or any rigid card) — it harvests better and works everywhere. If you want to keep using the FlexUG4, you’re stuck doing the keypad-wake trick on weak readers, and on readers with no wake mechanism (the elevator) it may just never work.
- Positioning helps a little (flat, dead-center, held longer) but it won’t overcome a fundamentally weak field.
Do you have an actual Gen4 Card?
If so test that.
That will confirm if it is a Chip issue or an antenna issue.
If antenna.
This will have a better chance of coupling.
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It sounds like your FlexUG4 is not installed, is that correct?
The Antenna is tuned for being under the skin, which will make a difference for coupling.
Whether that is enough to make a difference, I couldn’t tell you.
There is no real way of knowing without testing.
The older copper antenna FlexM1 is no longer avaliable, but the newer form factor is much smaller but the performance is quite similar.
Both are very good, but only testing will tell you if it will work.
Can you get a repeater sticker on the elevator reader?
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I will get a Gen4 card to test, and yes, my FlexUG4 is not installed yet. I see, because I thought the plastic packaging is so thin that it is the same as skin.
I will install it anyway since I am going to install it at P1, P2 or P3 as it is a good location for door reader.
If the Gen4 card works then I might get a dUG4T to install at my wrist just for elevators.
I don’t have a repeater sticker to test on the elevator reader sadly.