Can not send Firo (RuntimeError(ProcessError: Encountered invalid prev_hash))


I have tried several times now to send Firo using “Firo Electrum”, and I keep getting this error. Think I have gotten it before, but it worked when I used other outputs, tried all different outputs. new coins, old coins etc. Can not send no matter what I do.


It’s the same issue as here: Masternode reward got stuck in Trezor Electrum Wallet. · Issue #9 · firoorg/electrum-firo · GitHub

I was finally able to send Firo, but the only way I can do it with Trezor, is if I manually select 2-3 outputs, and then send a small amount at a time…

This is not very user friendly.

We will try to have a look at it but no development bandwidth available at this time.

I have the same issue, I tracked it down to being a 3.125 masternode reward payout that gives me that error whenever those coins happen to be selected.
The “fix” is to freeze those coins.

Over time I’ve now accumulated 3 of those trouble-makers that I’ll need to keep frozen until there’s a fix to use/spend them.

This is on firo electrum, connected to a Trezor … same issue on Mac as on Windows

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That’s the same situation I find myself in. I think this is a huge bug that’s existed now for years. I mean, money/FIRO that can not be spent is essentially worthless.

I now have accumulated 15 masternode rewards that I need to keep frozen or I get the invalid prev_hash when trying to send firo.

Some rewards I can spend just fine, others (lately most) are throwing that error … I’ve now updated my payout address to one outside of electrum.

If somebody ever figures out how to get such masternode rewards out of electrum, please post here :slight_smile:

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Is there any idea of when this can be fixed? I have now accumulated over 1000 Firo in masternode rewards, but I can not move the money. I just get this error message. So I can not set up a new Firo node or spend any Firo…

Will this be addressed when developing Firo Spark? Will transactions work better with Hardware wallets when this is released? I remember that last time I tested private transactions, all Firo sent to Trezor hardware wallets was impossible to move, because of a similar issue to the one I have now.

wow, 1K firo locked, that sucks

good news, I just managed to get my firo out of electrum
note, i did this on a windows pc (my main one is a mac, where it (in combination with trezor) gave me issues … just because I didnt want to touch my original setup. You could also for example use parallels to load a windows VM

anyways, what I did was:

  • I added a new wallet in electrum (file → new/restore)
  • enter some bogus name
  • standard wallet
  • i already have a seed
  • enter the recovery seed of my trezor
  • click on options and select bip39
  • continue continue leave everything default, can even leave the password fields blank

if you then see your firo balance, you can transfer them out without the need of your trezor HW and it will work

now if you dont see your balance (as was the case for me), delete this wallet, do the whole setup again but in the step where you click on options and select bip39, also check the box to “extend this seed with custom words” … then it will ask for the custom word and for me that was the passphrase that i use for my trezor … then it magically started syncing and my balance appeared, i entered the payment, pay and broadcast, done!

Im so glad I got mine out, thought they were lost forever.

Hope you have the same success.

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