There seems to be room for improvement. It's understandable that the download tool can't be delivered together with the needed copyrighted firmware files, but it could check if those files are present on the sd card and if they have the correct hash. It also could check if the files are the correct ones for the used system and it should not start the downgrade if it's not the case. All these things can be done manually, and implementing them in the downgrader would take time. Now it's released "as is", without those checks.
Further, I assume a hardware backup of the emmc would be the perfect solution to recover from wathever brick you might get. At least, I am intending to take one before I start messing around with it, no matter how tempting it is to start downgrading right away.
Further, I assume a hardware backup of the emmc would be the perfect solution to recover from wathever brick you might get. At least, I am intending to take one before I start messing around with it, no matter how tempting it is to start downgrading right away.