taken from upms-project.com
New Features: - Installer
You will need the following EBOOTS to the root of your Memory Stick before proceeding:
UPDATE.PBP (Only if you want to downgrade to 1.50 Firmware)
340.PBP (Only if you want to Install Time Machine)
360.PSAR (Only if you want to Install Time Machine)
New Improved Splashes
New Improved visual install proceedure
New Motherboard detection using Pommel, Tachyon & Baryon values. (Now displays your PSP model ie. TA-079.)
New Displays the available free space on your memory stick which updates as the install proceeds.
Renamed the Clean Nand items in Utilities menu, to stop confusion of people thinking it's installing the clean nands to the actual psp without creating a nand backup.
Added 390 Kernel 150 Addon
Removed writing of the full eeprom to the battery
New Dark AleX's Time Machine IPL can now be installed from the IPL menu, this also installs the config file which contains the LTrigger for booting to UPMS. Now no need to convert Pandora's IPL or install the IPL, just launch Time Machine from the Utilities Menu then select the firmware you want to install.
Disabled the battery menu for the latest PSP Slims V2.
New Random Serial Generator for when you want to make your Pandora Battery normal, creates a randomly generated hex number.
Now installs Despertar Cementerio V5 (TheJoker has had to be removed)
New Features: - Ultimate Loader
352M33 via Hellcats Menu
New PSP Motherboard detection
New Reboot to XMB option added. (TA-082 has troubles with display after reboot)
Added Free Memory Stick Space for visual confirmation.
Added Nand Backup direct from Ultimate Loader. (For Fat & Slim PSP's)
Added IDStorage Key Backup direct from Ultimate Loader. (For Fat & Slim PSP's)
Removed NandManager as NandTool by Cory is UPMS-Projects preferred backup/restore tool
You now can't use the excuse of I didn't create a nand backup because you won't be able to continue any firmware install, unless you have one either dumped via UL or Nandtool and this has to match the PSP's unique ID number.
After you have selected a firmware option to install, UL will either ask you to make a Nand, IDS Key Dump or both, unless you have a dump that matches that PSP.
We hope you enjoy this release.
The thing i like is that if you have UPMS already you don't need to reformat MS.
Just click on Clean MS for fresh install. Then just install.