Upgrading to 2.60 help

I have a PSP with firmware 2.01, I need to upgrade to 2.60 then downgrade to 1.50 but I need a way to do this without buying GTA:LCS, is it possible?
If so can someone give me a guide on how to run an update because I tried before with a 2.60 update and it didn't work.
Thanks in advance ~ S-B

Download the update file:Here
Then put the update file In the Memory Stick: PSP/Game/UPDATE/EBOOT.PBP
PS you have to make the UPDATE Folder Yourself Then Put The Update File (EBOOT.PBP) In The Update Folder.
Then on your psp go to the game section on the XMB then Go to Memory Stick Press X and Select 2.60 Update. That is how you update but to downgrade you need to check your motherboard if you have writing on the top right of the silicon chip when you open the umd drivehttp://xa.beareyes.com.cn/2/lib/200608/23/262/01.jpg that Means You Have A TA-082 Motherboard Which Cannot Downgrade But if you Dont have the writing You Can.But to the GTA Part you do need it you could just borrow it for a day or buy second-hand

Fourtunatly I'm not cursed with the TA-082 motherboard but dam, I need GTA, I'll just take a trip to eBay then...

Why not rent it?

Or borrow it from a friend?