Coldcard cannot read PSBT

[marc3535]

I cannot sign PSBT's with my coldcard. I use the latest version of Sparrow wallet. I manage to save a PSBT file on my sd-card, but when I put the sd-card in my CC and press "ready to sign" it doesn't find the PSBT but says "Coldcard is ready to sign spending transactions".

I have already updated Coldcard firmware to the latest version but it won't help, I have also updated my Sparrow wallet. The SD card has been delivered with my coldcard (so it is from coinkite) and it has been formatted in FAT 32.

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[RickDeckard]

Probably this[1] thread may be of use to you. More specifically this particularly entry:

I think I've figured it out. It's either that the transaction can be a max of 20 inputs, or the size of the transaction cannot exceed more than 384k bytes. The size of the transaction was the issue, not the number of inputs.

This presents a problem in that in order to get all of my remaining bitcoin out of my wallet, I'd have to do about 10 transactions. Is there no way around this?

[1]https://bitcointalk.org/index.php?topic=5348511.0

[marc3535]

Thank you. I read that thread already and it doesn't help me further. It's about sending too many inputs, but I only tried a transaction to send with 1 UTXO containing really not much BTC. So I think there should be some other issue.

[satscraper]

I cannot sign PSBT's with my coldcard. I use the latest version of Sparrow wallet. I manage to save a PSBT file on my sd-card, but when I put the sd-card in my CC and press "ready to sign" it doesn't find the PSBT but says "Coldcard is ready to sign spending transactions".

I have already updated Coldcard firmware to the latest version but it won't help, I have also updated my Sparrow wallet. The SD card has been delivered with my coldcard (so it is from coinkite) and it has been formatted in FAT 32.

Just to throw aside the crazy assumption. Did you insert the microSD  card by correct side? Try to pull it out  and insert again. PSBT's file might also be not readable on the premise that relevant contacts pins on  microSD  card were damaged somehow at the attempt to forcefully insert the card into coldcard's slot. Thus, try to use other card.

[marc3535]

Yes I use the SD cards correct side. I managed to also upgrade coldcards firmware using this SD card (downloading an upgrade file from the CC website) so the SD card itself seems just fine.

[RickDeckard]

This may sound dumb, but have you inserted the micro SD before turning on the Coldcard? If you have exported correctly the PSBT file (you can see how in this guide[1]), what happens after you select the option Ready to Sign?
[1]https://coldcard.com/docs/send-receive-btc/

[marc3535]

Actually today it worked out fine. Maybe it was an issue with not turning the coldcard on before inserting the SD card, I don't remember exactly how I did that previously. Anyway, everyone thanks a lot for your help and suggestions!

[Pmalek]

This may sound dumb, but have you inserted the micro SD before turning on the Coldcard? If you have exported correctly the PSBT file (you can see how in this guide[1]), what happens after you select the option Ready to Sign?

The OP has solved their issue without knowing exactly how. But it doesn't matter. You forgot to attach the guide explaining how to work with and export/import PSBT files. I guess you meant to link to Sending and Receiving Bitcoin for Beginners from Coldcard's official docs section.

[RickDeckard]

This may sound dumb, but have you inserted the micro SD before turning on the Coldcard? If you have exported correctly the PSBT file (you can see how in this guide[1]), what happens after you select the option Ready to Sign?

The OP has solved their issue without knowing exactly how. But it doesn't matter. You forgot to attach the guide explaining how to work with and export/import PSBT files. I guess you meant to link to Sending and Receiving Bitcoin for Beginners from Coldcard's official docs section.

My bad, the link ended up being lost in my drafts - thank you for pointing it out. I have corrected my post to include the referenced link.

[marc3535]

Hi, today I have again exactly the same problem unfortenately. My coldcard cannot read the PSBT file. If I press "ready to sign" it says "Coldcard is ready to sign". I contacted the Coinkite support and they suggest using another SD card, but this SD card I ordered directly from them. So I don't think this it the issue. I also followed all steps from the Coldcard website, their manual. Also it doesn't matter if I turn the coldcard on before inserting the SD card, or if I first import the SD card and then turn on the Coldcard.
Anyone has some ideas still? I'm thinking about purchasing a totally other wallet, like foundation passport, and inserting the coldcard seedphrase there. Getting quite frustrated with coldcard.

[RickDeckard]

The root cause of that erratic behaviour may well be a faulty SD card (assuming you are exporting correctly your PSBT file, which I believe you are). I have searched for that error message in COINKITE code repository[1] and I was able to found this section:

Code:

async def ready2sign(*a):
    # Top menu choice of top menu! Signing!
    # - check if any signable in SD card, if so do it
    # - if no card, check virtual disk for PSBT
    # - if still nothing, then talk about USB connection
    import stash
    from pincodes import pa
    from glob import NFC

    # just check if we have candidates, no UI
    choices = await file_picker(None, suffix='psbt', min_size=50,
                                max_size=MAX_TXN_LEN, taster=is_psbt)

    if pa.tmp_value:
        title = '[%s]' % xfp2str(settings.get('xfp'))
    else:
        title = None

    if not choices:
        msg = '''Coldcard is ready to sign spending transactions!

Put the proposed transaction onto MicroSD card \
in PSBT format (Partially Signed Bitcoin Transaction) \
or upload a transaction to be signed \
from your desktop wallet software or command line tools.\n\n'''

        if NFC:
            msg += 'Press (3) to send PSBT using NFC.\n\n'

        msg += "You will always be prompted to confirm the details before \
any signature is performed."

        ch = await ux_show_story(msg, title=title, escape='3')
        if ch == '3' and NFC:
            await NFC.start_psbt_rx()

        return

    if len(choices) == 1:
        # skip the menu
        label,path,fn = choices[0]
        input_psbt = path + '/' + fn
    else:
        input_psbt = await file_picker('Choose PSBT file to be signed.',
                                       choices=choices, title=title,
                                       batch_sign=True, escape="9")
        if not input_psbt:
            return

    # start the process
    from auth import sign_psbt_file

    await sign_psbt_file(input_psbt)

If seems that the code is made that if the code doesn't find any suitable files, it just presents you that message. Might be a silly question but if you have write protection in your card it can prevent the hardware wallet into making changes to the file, perhaps generating that error as well?

You could try to buy another SD card to see if the random problem persists. Even if you got the card from COINKITE, it doesn't mean that they are protected from faulty SD cards every now and then.

If you are thinking in buying another SD card, do consider grabbing one that is SLC (like Western Digital IX QD334 for example).
[1]https://github.com/Coldcard/firmware/blob/edge/shared/actions.py

[marc3535]

Thank you! Probably then I will try another SD card first, before dismissing Coldcard altogether. I can also use the Coldcard with a USB cable and forget about the SD card, but the reason I got a Coldcard was just to prevent this kind of direct contact of a wallet with the internet.

[RickDeckard]

Thank you! Probably then I will try another SD card first, before dismissing Coldcard altogether.

Understandable. Since you spoke about Foundation Passport you can find a lot of information (and feedback) about it on the official thread[1] before deciding in buying it or not.

Do keep us updated if the problem persisted after the new SD or not (for future reference).
[1]https://bitcointalk.org/index.php?topic=5441422.0

[marc3535]

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?

[satscraper]

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 file and sign again.

[Pmalek]

As satscraper metioned, try with a different software wallet. If you have a second computer, try that as well. Who knows, maybe you have found an uncommon hardware and software compatibility issue no one else has experienced. If nothing else works, request to send back the device and get a replacement one instead. I assume it's still under warranty. If it's not functioning as advertised, they have to send you a replacement.