Now I'm not a genius, everyone could do that.
No one did, so I'm here to guide you.
First thing: credits
First I want to say "THANK YOU" to some people:
Silica - for giving me some infos and Ideas AND testing
PixelButts and The Dark Lord - for files (Dark Lord's files has been deleted)
Bajunan - for ideas
Team molecule - for HENkaku
TheFlow - for VitaShell
major_tom - for VitaRW
Explanation
As you know since 3.36 we can no longer open PKG Installer, as sony patched it, but the app is still there. Why? I think that PSVita still uses that for installing PKGs, in silent mode or something like that. Silica found that it is called FAKE package installer. So we tought that there would be a REAL pkg installer. Well, kind of. On DEX vitas the PKG installer is bigger than the CEX one, and the DEX one actually works! So we replaced the CEX pkg installer with the DEX one, and it works!
How to get it
Well, you need VitaRW (You can find it on internet) and HENkaku with vitashell. Then you need this file
And any FTP manager on your computer.
Visit go.henkaku.xyz or use offline installer.
Then open VitaRW and when you read 0x000000 close it.
Open VitaShell and press select to open a FTP server. Connect via FTP to your vita from your pc. Browse to "vs0:app" and backup NPXS10031. Extract the file that you have downloaded and copy the extracted folder in your "/app" folder.
If you already got the PKG Installer bubble you can already open and enjoy it, else follow this guide or use this site
DON'T TOUCH FILES IF YOU DON'T KNOW WHAT YOU ARE DOING, IT COULD BRICK YOUR VITA!!!!!!!!




