I went to a game shop. The shop owner said that the PSP comes with three models, they are 1.0, 1.5 and 2.0. But I think they are just different in OS versions. But, the prices are different! He said that it cannot be upgraded nor downgraded. I think he's wrong but he said he's correct. If I buy a 1.0 PSP, can I upgrade it to v1.5 using a update(eboot.pdb) file? And... are all the language versions of 1.5 firmware the same? Or that firmware supports multilanguage? I have downloaded a Japanese version of 1.5 updater, but I'm afraid that my PSP will be covered by japanese characters when I switch on my PSP after that update.