The vast majority of old homebrews that do not work on the PRO custom firmware can be played quite easily - just use the LME firmware and leda plugin instead. Some apps and games will still refuse to boot, however. Can anything be done to rescue them?

The eLoader can be a powerful tool in this regard. In its default configuration, it is essential to launch homebrews such as Callisto and Realtech VR’s No Gravity. Its most interesting feature, however, is the support for custom configuration files.

Open loader1000.cfg in any text editor, and a large battery of options will appear:

[global]
# menu : which menu file to load
menu=ms0:/PSP/GAME/eLoader/emenu--.pbp

# Allow soft reset of PSP by holding LTrig+RTrig+START?
softreset=Y

# Return to the loader menu after soft reset, or go to the XMB?
resettoloader=Y

# Save and restore stack frame either side of running menu?
savestack=Y

# Clear RAM before the loader exits?
clearRAMonExit=N

# Emenu Wallpaper - new for eLoader 0.99
menuBackground=ms0:/PSP/GAME/eLoader/emenu_1000.png


###############################################################################
# Default loader behaviour                                                    #
#                                                                             #
# These can all be overridden on a per-EBOOT basis in later sections          #
###############################################################################

[defaults]
# Show confirmation menu before running EBOOT? [Y/N]
confirm=N

# Clear screen before running EBOOT? [Y/N]
clearscreen=Y

# Clear most of the screen before running EBOOT? (Terra Incognita) [Y/N]
specialclearscreen=N

# Pass startup parameters to EBOOT? [Y/N]
passparameters=Y

# Mandatory install folder for EBOOT [full pathname, must include final '/']
# mandatorypath= not specified in defaults

# Mandatory extra data folder
# mandatorydatapath= not specified in defaults

# Ignore fixed path strings found in EBOOT? [Y/N]
ignorefixedpath=N

# Process non-essential ELF sections? [Y/N]
readsections=Y

# Call .init section? [Y/N]
callinit=N

# Set GP value from REGINFO section if present? [Y/N]
gpfromreginfo=Y

# Set GP value from MODULEINFO if present? [Y/N]
gpfrommodinfo=Y

# Warn before automatically patching kernel apps? [Y/N]
patchkernelwarning=N

# Clear BSS + TEXT segments
initbssfull=Y

# Clear just BSS segment
initbsspartial=N

# Initial load to different area in RAM
loadhigh=N

# Fake unknown NIDs to always return 'success'
unknownNIDsAlwaysSucceed=Y

# Reset wifi libraries before starting wifi homebrew?
resetwifi=N

# CPU clock speed to use (note that if this is set as a default, then the
# user can't control it using the menu).  333 is the maximum.
# clockspeed=222

# Bus clock speed to use (111 is the system default.  166 is the maximum).
busSpeed=111

# Hold HOME to exit?  (Regardless of this setting, you can always use L+R+START)
# This interferes with some programs, and is unsupported by others.
# If you see strange key behaviour, turn it off.
exitButtonIsHome=N

# Call application's exit callback before exit?
callExitCallback=N

# Prevent the screen from automatically dimming?
doPowerTicks=Y

#*****************************************************************************/
#* Items below are new in 0.96                                               */
#*****************************************************************************/
# Use cautious memory manager?
limitedMemoryManager=N

# Limits thread stack size : this is the maximum size in bytes that will be
# reserved per thread.  Requests for stack sizes larger than this will be
# reduced to this size.  0 turns off stack size limits.
limitStacks=0

# Delete main thread when it exits?
deleteMainThreadOnExit=Y

# Clear RAM after running menu?
clearRAMaftermenu=Y

# Kill system threads?  (Might give better stability)
killThreads=N

#*****************************************************************************/
#* Items below are new in 0.97                                               */
#*****************************************************************************/
# Warn user with fatal error if wifi libs couldn't be loaded
disableWifiWarning=Y

# Relocate EBOOT to a specific address?  (normally off, used to refine "loadhigh")
# The format is relocateCodeTo=0x12345678.
# Valid addresses will probably range from 0x08800000 to 0x09000000
relocateCodeTo=0

A Windows app makes it possible to get a signature for each EBOOT, so that the custom settings can be added to the file.

A full online guide to the eLoader is available here.