Neuron has recently updated his ME CFW for both hackable and non-hackable PSPs

The changelog is available below:

v9.2
— Fixed a bug when ISO open in XMB.
— Added a PBOOT.PBP execute option.
— Fixed a UMDdrive noise when enter sleep mode.
— Update Plugin loading. Both ms0 and ef0 plugins are loaded in XMB.(05g only)

For 6.39 ME (for fully hackable PSP’s only)

Requirements:

• A PSP with 6.39 OFW (if you don’t have it, you can follow this guide on how to upgrade to 6.39 OFW)
• Download 6.39 ME 9.2 : Mirror 1 | Mirror 2
• Download 6.39 OFW: Mirror

How to install 6.39 ME 9.2:

• Extract the release_639me.zip file.
• copy UPDATE folder at ms0:/PSP/GAME/.
• Extract the PSP_639_FW_UPDATE.zip
• Rename the extracted eboot to 639.PBP
• Copy 639.PBP folder into at ms0:/PSP/GAME/UPDATE
• Run the installer from the XMB

For non-hackable/partially hackable PSPs
Requirements:

• A PSP with 6.39 OFW (if you don’t have it, you can follow this guide on how to upgrade to 6.39 OFW)
• Download 6.39 LLCFW ME 9.2 : Mirror 1 | Mirror 2

How to install 6.39 ME LCFW 9.2:

• Extract the release_639lme.zip file.
• copy installer folder and launcher folder at ms0:/PSP/GAME/.
• Run the installer from the XMB
• Press x to install LCFW.

Important Notes to enter RecoveryMenu?
From XMB :Open VshMenu and select “Enter Recovery ->”
From LCFW:Execute “639 launcher” again.
From OFW :Execute “639 launcher” with hold “R”.

— Credit —
some1: For his sceHttpStorageOpen kxploit.
liquidzigong: For his 639kxploit POC.
bbtgp: For his PrxEncrypter.
Draan: For his kirk-engine code.
J416: For his rebootex sample.
N-zaki : For providing PSPGo from him.

source Neuron’s Twitter