I successfully made my OLD 3ds boot into emunand using this fork of cakesfw (
https://github.com/fox8091/CakesForA9LH)
Of course you have to trim 0x12000 bytes of Cakes.dat.
Also when you boot, both screen will remain black.
But CakesFW configuration is still working behind black screen.
Just memorize the key stroke which checks patches and toggles autoboot before installing arm9loaderhax and press that key storke after the installation)
(↓ -> A -> A -> ↓ -> A -> ↓ -> A -> B -> ↓ -> ↓ -> A -> A-> A -> B -> B -> A)
Don't apply 4th patch of CakesFW.