While it is possible to rename the RM-505 ROFS2 to the RM-507 and flash it, the keyboard layout, even when changing it to english, does not map to the keyboard we have on our RM-507. If it would be un-important keys, that would be one thing, but the period and comma key is one that does not work, and all of the symbols do not match up with what's silkscreened on the keyboard.
OK, I've spent some time to do the following:
* take a vanilla RM-507 ROFS2 and add the Russian input language
and I succeeded. The trick was to unpack \sys\bin\PtiKeymappings_505_11.dll with petran (i.e. petran -nocompress PtiKeymappings_505_11.dll), then locate the first string with the sequence 1234567890@/ and replace chars after that sequence with a hexeditor to match RM-507's keyboard -- this way you will get English keyboard mapping almost properly. You also need to copy \private\10009d8f\ecom-2-0.spi from RM-505's ROFS2 (in my case I just hacked RM-507's to use Russian instead of Talagon and then corrected relocations inside the file), and finally, if you want to have T9 you need to copy \sys\bin\Zi8Russian.dll from RM-505's ROFS.
This should give you an almost properly working QWERTY input on N97. The thing I spent 2 days to figure out was to figure out how to get a dot/comma key working in the English layout (since this key was always mapped to Russian layout), and finally I did it: by hex-editing PtiKeymappings_505_11.dll even further.
I've attached the modified files. Unfortunately, my longer post where I tried to describe the mapping I implemented was lost due to a glitch and I don't wanna spend a lot of time again to re-create it. OK, briefly, the layout for the English keyboard of RM-507 matches marks on keys with 5 additional key combinations: Sym+Shift+k = |, Sym+Shift+l = ~, Sym+Shift+. = `, Sym+Shift+n = |, and Sym+Shift+m = ~ . For the Russian layout, the 2nd row is almost preserved (i.e. RM-507's key marks correspond to the layout), and the 3rd row is almost corresponding to the original Russian layout.
If you re-use my work I'd appreciate a credit
P.S. modified the message since I replaced Talagon (or what the name for Pilipino language in RM-507 is), not English