Neither of these programs can brick your PSP, as neither accesses flash0.
This version includes some updates for 1.5 users.

To install:
* 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.