in OSDHOOK.S
for PS2 bootstrap:

                        li          a0, txtPS2ELF
                        jal         strstr
                        lw          a1, 0x00(s2)
                        bnez        v0, _done
                        nop

and in the ps1 bootstrap this:

                        li          a0, txtPSXEXE
                        jal         strstr
                        lw          a1, 0x00(s2)
                        beqz        v0, _noAuth
                        nop

then in the BOOTMENU.PBT change all
    SET "IS_HOMEBREW" "0"
to
    SET "IS_HOMEBREW" "1"