I managed to kill f3write, so f3probe could access it:
ene@coyote:/mnt/disktest$ sudo f3probe --destructive --time-ops /dev/sdm
F3 probe 8.0
Copyright (C) 2010 Digirati Internet LTDA.
This is free software; see the source for copying conditions.
WARNING: Probing normally takes from a few seconds to 15 minutes, but
it can take longer. Please be patient.
Bad news: The device `/dev/sdm' is a counterfeit of type limbo
You can "fix" this device using the following command:
f3fix --last-sec=124050943 /dev/sdm
Device geometry:
*Usable* size: 59.15 GB (124050944 blocks)
Announced size: 1.91 TB (4096000000 blocks)
Module: 2.00 TB (2^41 Bytes)
Approximate cache size: 1.00 MB (2048 blocks), need-reset=no
Physical block size: 512.00 Byte (2^9 Bytes)
Probe time: 2.07s
Operation: total time / count = avg time
Read: 311.9ms / 4212 = 74us
Write: 1.75s / 24740 = 70us
Reset: 1us / 1 = 1us
gene@coyote:/mnt/disktest$
No faster than it is, its not worth the f3fix effort, I can buy
reputable, much faster sd cards at 1/3rd the cost.