This guide:
https://gbatemp.net/threads/guide-r...mware-w-o-upgrading-to-10-3-or-higher.413368/
Basically it involves using CN/OOT to boot the homebrew menu, launch pasta. Boot OOT/CN again, load FBI and install the regular 0.4.2 sysupdater as a CIA. Then shut down, do the whole CN/OOT boot again, launch pasta, run Sysupdater and downgrade. It will install a few titles and then reboot to a normal 9.2
(Normally what happens is it crashes prior to replacing NVER, so your payload has to reflect that. So your true payload on a frankenfirm would be 9.2.0-27U in this case)
Also, if your unit crashes during the first downgrade, you need to remove the SD to boot it back up.
Anyways, I guess I should say "DO THIS AT YOUR OWN RISK"