Don’t trust the Yoroi browser extension under any circumstances. Mine crashed with 722 ERG in it, and it appears that the mnemonic is useless in anything except Yoroi…and Yoroi itself will repeatedly crash again and again instead of allowing you to restore it.
Putting your ERG in a Yoroi extension wallet is akin to leaving a pile of twenties on the street.
If you know how to recover a Yoroi generated private key, or know of some way other than Yoroi to open a Yoroi wallet, please help!