How to bypass BitGo's error when using a Ledger wallet
BitGo recently updated the version of its bitcoinjs-lib dependency, but failed to update the code that interacted with legacy wallets that relied on Ledger hardware wallets. This triggered a
r.bufferutils.varIntSize is not a function error whenever trying to use the funds in the wallet. Following is a workaround you can use to manually patch the error, and get your funds out of BitGo.
Disclaimer: I set up this workaround to help a friend rescue their funds. I have no idea if it works for every instance of this error, and it may lead to loss of funds. I strongly suggest that you try it out with a small amount before you attempt to remove all your bitcoin from BitGo.
The problem seems to happen when interacting with a legacy wallet managed by a Ledger hardware wallet. You have a legacy wallet if BitGo displays the following notice when you open your wallet (fun fact: the link to the instructions to mi