I am just not explaining well. I worked out the system that should be universal to both roms. I gave a quick 7 step method for the att 3.51 only rom above to make it easier.
Let me show you how it works on your example.
Attachment 83813 (Click on it to expand picture, not sure why my attachment is so small)
The string inside the black frame box is the one that is found in most roms including the att 3.51 (E1 02 38 83 E1 01 3C 83 E1 80 00 ). and you can see that 3 bytes over are the values 10 E6. This indicates that the rom is already set to manual pagepool (because of the E6) and is set to 16 meg page pool (
because 10 = 16 meg page pool in hex 1F = 31 in hex, 20 = 32 etc)
Change that 10 value to whatever size you wish. remember its hex so 0E = 14 in decimal.
Note that the string in the black box can only be used to find the initial set. When you search for the second set use the string you highlighted and then change the previous 2 bytes. In your example again it is 10 E6 just left of your black highlight. make your first change then search again for the string you have highlighted (A0 03 00 E0 84 05 03 00 00 ) and two bytes previous will be 10 E6 again. Make same change there and save it.