Ledger hardware wallet is not supported

[valo]

Seems like the library uses the signTypedMessage method, which is currently not supported by hardware wallets like Ledger. See MetaMask/metamask-extension#5792

The error that is received upon trying to sign the message:

MetaMask - RPC Error: MetaMask Message Signature: Error: Not supported on this device

I am wondering if it's possible to use a different type of signature, so that hardware wallets can be supported. This problem will be a significant obstacle in implementing the gasless system for a mainstream usage.

[nourharidy]

Unfortunately, EIP712's signTypedData is required by the MCD DAI contract.

That being said, it may be possible to use web3-provider-engine to construct an intermediate web3 provider and support signTypedData by creating a provider middleware which would use Ledger's plain signatures to construct signTypedData signatures.