My lost 1.5 Jap psp was returned to me...

Hi,
As I posted in the intro section, I am a Marine and I have to return to Iraq in a couple of days. Through my many movings, my Jap 1.5 psp was lost. Now it is found. I can see devhook 0.51 beta on it and some kind of firmware emulation for 2.6 up to 3.01 on it. A few game isos and that's about it.
It's been so long since I got to even use this thing that I have almost forgotten how!
Could someone tell me how to check which firmware I had upgraded to?? I would like to update this psp and I don't know if I should install the newest firmware or if I have to do it oldest to newest, one by one. I see the package is now marked 3.9 M33. My Sony nag tells me that I have to update to 2.71 if that helps any!
Please help me with the update process, I want to leave this psp behind for my son. I would hate to lose a 1.5 in Iraq!
Also, can you use homebrew on the slims? I thought about buying one of those to take with me. The sand is hard as h--ll on things. Would like to play some games during down time, but I can't have all these little umds floating about.

I am sorry that I don't have time to read everything and learn how to do the firmware updates myself. I am only home for about 1-2 hours before time to hit the sack!
Thanks in advance to all that help me, I am grateful,
Semper Fi

To check your firmware

Go to "Settings"(far left)
Then go to "System Settings"
Now scroll down to "System Information" and press "X"

If you have 1.50 still, then upgrade to 3.52 M33.
The M33 installer can be obtained on Dark-Alex's website
Here is the 1.50 EBOOT
and lastly the3.52 EBOOT

If your firmware is 2.00-2.71 email me and I'll send you the 1.50 dumps.
You can find the downgrader you need on this site
go to the downloads section and search for it. Good luck!

Thanks roxfox64,
I checked my firmware, it's a Jap 1.5 still. I'm sorry to seem so stupid, I haven't been able to use this thing for ages.
Is there any way for me to make a back up of my 1.5 firmware before I try this? I assume I should reformat my memory stick also?

I gather from what little I have been able to read that I can buy a slim psp and downgrade it.

I appreciate your help, I've got to leave in a little over a day now and I would like to get this done and leave it for my son.
Thanks again,
Semper Fi

If you want to do a backup the only thing you can do is make a pandora battery,
but you shouldn't need to worry about that.
Just run the 3.52 M33(release) update and then obtain 3.52 M33-4(also on Dark-Alex's site)
As far as reformatting your memory stick goes, you most likely don't need to.
On that note. You need more than 32 MB of free space on your memory stick.

And also, You're much better with a phat. If you do get a slim don't sell your phat,
or at least make a pandora before you do.

I plan to leave the Jap 1.5 behind with my son. For the psp to go with me, should I buy a slim or look for a phat on ebay?

Stick with the phat as you have more homebrew support
On ebay search for "M33" you'll find a few phats with versions
of M33 pre installed for a decent price. Usually 90&↓.