Extreme Link:

1. Install Extreme Link
2. Open Extreme Link
3. Select Drive
4. Double click Up or down into to the ISO folder. - ISO, CSO, DAX files will show on the right hand window (NOT Selectable)...
5. Click Execute - This will toss commands to usbhostfs.exe and open with that folder with the files...

Note: You must double click up or down on the folder files to get anywhere. This is called browsing for you noobs.

Dev Hook: Install
1. Install Dev Hook v4* full(USB MOD'ed - Must Have)

Dev Hook: Usage - You must be in PSP Firmware 1.5

1. PSP\GAMES\Memory Stick\DevHook or DevHook Shell
2. Put in a UMD Game or UMD Sampler Disc
3. Select DevHook or DevHook Shell. - Wait for reboot

3.1 At this time if it asks you for the drivers you will need to install the drivers I have provided in with the installer. Then Follow the driver install instructions Provided in the installer.

4. Settings are as follows:
UMD MOUNT....> ISO ANYUMD - Enter(X-O)
UMD VERSION..> 2.xx to 2.0 - Enter(X-O)
FIRMWARE......> 2.71 - Enter(X-O)
CPU CLOCK.....> 222MHZ / 111MHZ - Enter(X-O)
BOOT SELECT.> REBOOT XMB
OTHER..........> USB OPTION(X-O) ...> ENABLED (You might have to disable this then enable it for it to see your connection) - RETURN

5. Scroll up to UMD SELECT - Enter (X-O)

Note: Once this has been done correctly. You shouldn't have to go through all the settings again. Accept for maybe the USB enable and disable

6. Select your game - Enter(X-O)
7. Scroll up to START - Enter(X-O)

Wait for the Game to load then play! 

THIS WORKS ONE HUNDRED % FOR ME ON MY 1.5 PSP.

IRSHELL 3.6: OE Install
Copy all files needed from IRSHELL 3.6 to PSP

On your PSP, Reboot to Recovery Mode.
Go to Advanced / Toggle USB (flash0)
Copy /PSP/GAME150/btcnfpatch/irspatch.prx to flash0:/kn/irspatch.prx

Edit the flash0:/kn/pspbtcnf_game.txt file and add the irspatch.prx to it. 
The entry needs to be added between "$/kd/ata.prx" & "$/kd/umdman.prx"

Sample:
$/kd/ata.prx 
/kd/irspatch.prx 
$/kd/umdman.prx 

Save file
Exit

Toggle USB (flash0) again or Eject PSP  On Extreme Link / Tools
Back
Exit

If you edited the vsh.txt, PSP should boot into IRSHELL

USING IRSHELL 3.6
For ISO / CSO Files see above. All other files (PSX Eboots) need not be.

USBHost
USBHostfs
Notes: When trying to use the USBHostfs PC Game pad file. You must reselect the file in options before executing it. This is a bug in USBHostfs PC Game pad file and not of Extreme Link. USBHostfs Xbox file does not have this issue.
Solution: 
1.	Buy an Xbox USB Game Pad. And use the USBHostfs Xbox file
2.	Go to the maker of USBHostfs PC game pad and complain
3.	Dont use the USBHostfs PC Game Pad file.
Directions
1.	Turn on Extreme Links USBHost  Must be config in options.
2.	Toggle USBHost on the IRSHELL  Wait for symbol Comp:/0
3.	Press Triangle  Youll see the Menu screen
4.	Press Triangle Again  Youll now see 
Ms0:/
Disc0:/
Nethost0:/
Usbhost0:/
5.	Select USBHost - X
6.	Select game  X x2 - If Config'ed for Confirmation

NETHost
Notes: After trying to connect with IRSHELL NETHost. I come to the conclusion that having a WEB Encrypted renders the use of the IRSHELL NETHost. If you encrypted the WEB with a passkey youll need to undo it. Youll also need to change that in your network setting on the psp. In till IRSHELL Puts in an encryption key value, this needs to be undone.
1.	Turn on Extreme Links NETHost  Must be config in options.
2.	Toggle NETHost on the IRSHELL  Wait for symbol Comp:/0 lower right
3.	Press Triangle  Youll see the Menu screen
4.	Press Triangle Again  Youll now see
Ms0:/
Disc0:/
Nethost0:/
Usbhost0:/
5.	Select NETHost - X
Select game  X x2

USB Dongle: IP 192.168.1.102
Note: The Dongle was used on the same comp that the NETHost was opened on. I could not get it to connect on other comps with the Dongle. In Short. Youre on your own for settings.

IRSHELL Config:
Non-MS Media Access: Enabled
XMB Network for NETHost:  YOUR-HOST - 3-4 Selects host
NETHost IP/Name (AP): 192.168.1. *** - Used Comp IP: 192.168.1.100
NETHost IP/Name (Adhoc): 192.168.1. *** - Used Comp IP: 192.168.1.100
NETHost Port: 7513  Must match Extreme Link/Options/NETHost  Port

O to Save


Good Luck!!!

P.S If you have installed the drivers in the wrong place try searching deleting these 2 files libusb0.dll & libusb0.ocx then reinstall the drivers from the installer for proper install. If asked for drivers redo the 3.1 directions from above..