I've been thinking that the easiest way to tell from the shipping box / PSP itself what firmware is installed would be from the
serial number of the PSP.
There seems to be 2 parts to serials, the P-number and the S-number:
The P number seems to (possibly) be regional and stays the same across a batch of consoles. The S-number is the serial number as shown inside the battery compartment.
I'm thinking maybe we could build a list of serial numbers against Original Firmware version? Unless there's already one out there somewhere? So to get things moving here's some real samples that have been through my hands, the final two digits and letter obscured for anonymity...
These are all UK/Eire spec European consoles
PSP-2003PB
Regional ID = CEK
Box Letter = A
Date Code = 7D
8 digit P-number = 27401019
7 digit serial = 03835XX
OFW = 3.71
PSP-2003PB
Regional ID = CEK
Box Letter = ?
Date Code = ?
8 digit P-number = 27401019
7 digit serial = 05310XX
OFW = 3.80
PSP-2003PB
Regional ID = CEK
Box Letter = ?
Date Code = ?
8 digit P-number = 27401019
7 digit serial = 05501XX
OFW = 3.90
PSP-2003PB
Regional ID = CEK
Box Letter = F
Date Code = 8A
8 digit P-number = 27401019
7 digit serial = 05893XX
OFW = 3.90
PSP-2003PB
Regional ID = CEK
Box Letter = G
Date Code = 8B
8 digit P-number = 27401019
7 digit serial = 06643XX
OFW = 3.90
PSP-2003PB
Regional ID = CEK
Box Letter = G
Date Code = 8C
8 digit P-number = 27401019
7 digit serial = 07583XX
OFW = 4.01
As you can see, for this region of consoles (other regions might have different blocks of serial numbers reserved) if your serial number is 06643XX or below you should be good to flash :thumbs:
If your serial is 07583XX or higher then

sorry!
Hope this helps - any other contributions would help narrow it down, especially for other regions of the world.