Old version of firmware (1.5.2). I know PIN but I don't have the seed ▫


I have some btc in a trezor with 1.5.2 firmware. I know my PIN but I don’t have the seed.
I can get to https://wallet.trezor.io/ and see my accounts. However, when I try to transfer btc to my another account I get an error:
Failed to send transaction
Error details: Failed to compile output

I know updating firmware should help, but since I don’t have my seed I’d rather find a way to extract btc before the update.


Hi @kidzik

Not knowing the seed is a very risky situation you put yourself into. Beware, performing firmware update may fail, and then the device would be completely erased, including the seed stored on the device.

Anyway, you can try access your wallet by using our older Trezor Wallet available from https://old-wallet.trezor.io/#/ and trying to send your transaction again.

You need to move your funds to some safe place ASAP. Only then can you proceed with the firmware update without risking permanent loss of funds.

Thanks @pavel!

In old-wallet.trezor.io I also get an error
Failed to send transaction
Error details: Failed to compile output
when I try to send a BTC transaction. It doesn’t get to the PIN stage just fails after I click send.

Do you have any open-source implementations from ~4y ago that I could use? Or rather my best bet is still to update the firmware and pray?


Nvm, I found the seed (buried 5y ago :), and I installed fresh firmware (1.5 → 1.10) without any issues with no need to restart from the seed.


My sister lost her seed phrase but has her pin #. The firmware is very outdated.

My intention is to unlock the wallet, send the coins to another wallet, and factory reset the device (to recapture the seed phrase – better this time!).

Any tips on working with very outdated firmware / brower extension, to achieve this?