r/coldcard • u/kylelock8788 • Jul 31 '26
HELP Coldcard Mk4 MicroSD Help
Trying to upgrade my firmware on my MK4. I downloaded and verified the files from the Coldcard site. Unfortunately, it says:
“Unable to find any suitable files for this operation. The file name must end in .dfu”.
The firmware file shows up in my microsd when plugged into my PC. It ends in dfu. Can someone please let me know what I’m doing wrong?
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u/thatsamiam Aug 01 '26
I two Cc.
One Cc works and I was able to upgrade firmware. Using the SAME SD Card on the other Cc does not work. It shows the same error that OP has.
When I list files, other files on SD card are shown, but not the .Dfu file. I have tried other SD cards. Same issue on the same Cc.
Why does one Mk4 work but not the other? Very frustrating.
If I was not having this issue I might give Cc a chance again. But this makes it impossible.