just installed a9lh on a o3ds xl. didnt follow the guide, since i did it n my 2ds before the guide was written.
instead of using an emunand, i just downgraded sysnand. it gave an error halfway through, and booted into "2.1" with the 9.2 browser and some other titles. some helpful people on #cakey let me know that rxtools 2.5.2 would work on that frankenfirmware, which would let me run sysupdater again to try the downgrade again. worked perfectly.
i have hardmodded all the consoles ive done this on, but at this point pretty much everything seems to be recoverable without one. at least on the o3ds.