need modded bios to OC higher

i have a mobile XP 2600+ and my mobo (gigabyte ga-7n400 pro2) bios will only let me overvolt to +5%, +7.5%, or to +10% of the standard vcore (1.65v). for some reason, with this mobile chip, the +10% vcore only shows up as 1.72v in cpu-z. i'd like to be able to give this chip up to 1.8v in order to get stable performance at least above 2.60 Ghz (right now max stable is 2.56 Ghz, even if i raise the multi and lower the FSB). can anyone point me in the direction of a modded bios that can give me the option of a higher vcore setting? thanks!

AMD XP-M 2600+ @ 2.56Ghz (12x213 @1.72v)
Gigabyte GA-7N400 Pro2
Geil 2x256MB PC3200 (2-3-3-11)
Gigabyte Radeon 9200 128MB VIVO
WD 36GB 10,000RPM 8MB SATA
Maxtor 40GB 7,200RPM 8MB ATA133

thanks

AMD XP-M 2600+ @ 2.56Ghz (12x213 @1.72v)
Gigabyte GA-7N400 Pro2
Geil 2x256MB PC3200 (2-3-3-11)
Gigabyte Radeon 9200 128MB VIVO
WD 36GB 10,000RPM 8MB SATA
Maxtor 40GB 7,200RPM 8MB ATA133