The only point to be considered is to ALWAYS but ALWAYS but ALWAYS but here´s again:
ALWAYS use SOFTMOD or HEN.
and DON´T install Custom Firmwares. (those which aren´t 'softmod')
here´s why:
1. CFW: Any motherboards containing chipset TA085 or less (some TA088V1, V2) can DO install a custom firmware. What do this mean? A CFW will let you have a system menu already hacked, allowing you to have an emergency boot (hellcat flash recovery), and have a already unlocked PSP upon a cold boot. Also you can access registry hacks like improve memory stick speed, etc.
Any psp over pcb TA088V3(+) will include the condemned motherboard of the death.
Installing any custom firmware/content on flash0 (the main memory disk and OS for PSP) will be detected by an anti-piracy check done by hardware, and bricking your PSP without any chances of restoring it).
That´s because neither motherboard TA088V3 or higher can do pandora battery
(a low level recovery tool which enables you to install homebrew, and repair bricks rewriting healthy clean firmware onto flash0, also it is known that model TA090V1 it IS capable of pandora battery)
So in other words, you can´t do pandora, so you can´t install ANY CFW (custom firmware)...
BUT... you can do...
2. SOFTMOD : you can use a HEN (homebrew enabler) which runs off system´s RAM thereby NOT being detected by the hardware check i´ve mentioned before on newer motherboards, so you must enable this "hacked XMB" (where XMB means the PSP´s OS) which will allow you to load newer ISOS, and load homebrew. But, if your PSP ever shutdowns, you lose the hacked FW, and must re-enable it from XMB. But luckily you can use the sleep function from your PSP and have your PSP being charged frequently so you can keep the softmodded FW hack upon a warm start.
If you want to play PS1/PSX games then that´s another story. Just few days ago a good respected hacker released 6.35HEN with PSX compatibility. (on 6.XX OFW 'OFW= Original Firmware', you can´t play PSX backups even using a hacked fw) so you should start from there once you´re ready to play PSX backups.
But, DON´T YOU EVER DARE TO DOWNGRADE FIRMWARE TO 5.XX at least yet. Because while it was successfully done, there´s a heavy risk of bricking (which sadly you won´t be able to survive if it ever happens to you) so just stick to 6.xx for now and any HEN (6.xx HEN) softmod will do.