hi !
everything is linked with your PSP version :
new versions (ie 3000) = no flash of the firmware possible (well it's not easy...).
unlike DS, there is no special chipset for PSP (well you have one, but it's expensive and not very easy to solder).
The only way is to "softmod" and reflash your bios in order to run hombrew (and ISO.... which is piracy !!).
Sony is aware of this and the new version is really more secured compare to PSP 1000 or 2000 (some models only...).
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