Current MetaMask requires Ledger users to connect using the Ethereum app, even if the user actually intends to use MetaMask to connect to an alternative EVM network with its own Ledger app, such as RSK. If the user tries to connect their Ledger when the RSK app is open, they will see an error “UNKNOWN_ERROR (0x6a15)”.
Users of non-Ethereum EVM compatible chains that have their own Ledger app (such as RSK) should be able to connect their Ledger to MetaMask with the app for that chain.
Other wallets such as Liquality and apps such as Sovryn enable RSK users to connect their Ledger using the Ledger RSK app, which enables users to interact with RSK apps using the address on the EIP-1191 compliant RSK derivation path
m/44'/137'/0'/0/N. When the user switches to using MetaMask, this workflow and the whole UX is disrupted because the user can only connect Ledger to MetaMask using the Ledger Ethereum app and interact with apps using the address on the Ethereum derivation paths hardcoded into MetaMask.
Possibly a dependency: github .com/MetaMask/MetaMask-extension/issues/8698
(sorry to break the URL, this forum would not let me put a link in the post)