On Solana, some apps construct transactions with an additional account to a transfer instruction, making it a multisig, despite transfer not actually supporting multisig.
It's done on purpose to prevent the TX from being broadcasted early, some wallet extensions do that immediately and Jupiter needs to be in control when it's submitted.
But our FW specifically checks if an instruction supports multisig and fails: https://github.com/trezor/trezor-firmware/blob/main/core/src/apps/solana/transaction/instruction.py#L127
An example of such transaction:
trezorctl solana sign-tx -n m/44h/501h/0h/0h 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
Related Slack thread
On Solana, some apps construct transactions with an additional account to a transfer instruction, making it a multisig, despite transfer not actually supporting multisig.
It's done on purpose to prevent the TX from being broadcasted early, some wallet extensions do that immediately and Jupiter needs to be in control when it's submitted.
But our FW specifically checks if an instruction supports multisig and fails: https://github.com/trezor/trezor-firmware/blob/main/core/src/apps/solana/transaction/instruction.py#L127
An example of such transaction:
Related Slack thread