Skylark has diligently put together a couple programs for the PSP. The first is a Font Hack installer, which will automatically enable or disable the font hack. The second is a button swapping hack that will switch the functions of the X and O buttons.
Neither of these programs can brick your PSP, as neither accesses flash0.
* Download the programs from this link.
* From the ZIP file, copy the "fontmod" and "psp" folders to the top level (root) of your memory stick.
It's that easy! Copy your user-made fonts into the "fontmod" folder on your memory stick. Remember to rename them to ltn0.pgf.