I started playing with my Pine 64+ quad-core ARM64 board again
recently. I have a 16GB Samsung EVO microSD card I was using
previously. I started out by zero'ing it:
dd if=/dev/zero of=/dev/sdc bs=1M status=progress
which seemed to finish fine. But when I remove and re-insert it, it
still has data on it. Double-U Tee Eff? I have tried the same
process on three different machines with different methods of
connection (in an SD adapter in a USB-SD reader; in the SD adapter in
a laptop SD slot (probably still USB internally); and directly in a
microSD slot in a second laptop).
I get no warning about being read only. The writes seem to occur
successfully and fully complete. I sync before I remove the media,
plug it back in and all the old data is still present.
My initial attempt to google this was unsuccessful (most people point
out the write protect tab, not my problem).
Any similar experience, and/or clues for recovery?
Thanks in advance.
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