That's not a thing, be more sensibles.
Okie, so like Trimesh explained, you can't just "unlock" the jap consoles via code.
You can however (and this works in caetla/explorer and other stuff to) just:
1- put a spring or something in the cd lid sensor so it keeps spinning with the tray up
2- start the psx with a black disk in
3- let it spin for a few secs
4- just grab it while it's spinning and swap it out for an import/cdr
5- boot the game via your cart
"Enable Swap" in unirom just stops the disk so you don't have to grab it while it's spining, which is a little better for the machine.
CDRs are still bad for the laser, long term.
IIRC in older action replays you had to go into the cd file explorer on the black disk, then back out first.
Explorers should be fine
You need a slightly different swap if not using a cart (e.g. the normal BZZZZ..wooosh,blingblingbling screen)
There are pure-caetla rom hacks (Ahoy 0.34 for example) which auto-stop the CD for you. (completely off topic, but it's pretty cool, they stuck the code for that in the unused portion of the license text. I like that)
Edit: Totally forgot
There used to exist unlicensed black disks (by datel or something) that let you boot imports and CDRs the same way. IIRC You could also do the same with the XPlorer CD version (CD9000 or something)