ANyone got a link to the alphabet list and the OS's

Ok I need to know again what letter's have which OS and which letter the new MB's started with. My friend is going to return or sell his TA-082 PSP and we are going to find him an older one. So does anyone have a link to or know the letter and os combo?

K and lower are 2.6

I think my friends was a K and it was a TA-082 board also. Did the TA-082's start with K?

No Letter = 1.50 (North-American release) Confirmed
A = 1.50 Confirmed
B = 1.51 Confirmed
C = 1.52 Confirmed
D = 1.52 Unconfirmed (multiple version reports)
E = 1.52 Confirmed
F = 2.00 Confirmed
G = 2.01 Confirmed
H = 2.50 Confirmed
I = 2.60 Confirmed