Hi, I tried this today with another SD (taken a bit of time because I had some problems with bitcoin core) but it still doesn't work. If I insert the SD in my coldcard containing a PSBT, I get "Coldcard is ready to sign spending transactions" after I enter "Ready to sign". Any other suggestions? Maybe my Coldcard doesn't work properly?
One more assumption.
The problem may be related with PSBT file created by Sparrow wallet rather than with ColdCard .
To exclude this hypothesis, try to pair ColdCard with other software wallet, let's say with Electrum or Specter , create new PSBT and sign again.