Internal error: remote error: Long"

[ostermayer]

This error is generated when signing a transaction with a size that exceeds the max coldcard wire protocol. I believe this is MAX_TXN_LEN of 384kb.

Perhaps the error could be more descriptive to instruct the user to attempt signing via SD card or use another device for signing.

[k9ert]

@doc-hex can we have a fix in coldcard for this?

[doc-hex]

from public_constants.py:

# Max PSBT txn we support (384k bytes as PSBT)
# - the max on the wire for mainnet is 100k
# - but a PSBT might contain a full txn for each input
MAX_TXN_LEN = const(384*1024)
MAX_TXN_LEN_MK4 = const(2*1024*1024)

So on the Mk4, the max PSBT size is 2MB.

I was not able to find "Long" as an error message in our code. We can certainly make that better, but will be hard to trigger to on Mk4.

[k9ert]

@ostermayer it's not clear to me how exactly the error-message look like. Can you look into the logs and/or make a screenshot?