FreeBSD on GA-E7AUM-DS2H with Over 2GB of RAM

Written by Tatyana Hiko < tatyana at miko dot org >

=ChangeLog=
Initial Release (Dec 1, 2009)

Japanese version

Abstract

Gigabyte technology's MPC7A Motherboard GA-E7AUM-DS2H has a bug in its BIOS. (This bug still exists in the latest BIOS, version F4)

Due to this problem this motherboard cannot drive FreeBSD stably if

• you are using the onboard VGA, and if
• you are using over 2GB of memory.

You can avoid this problem by

• using PCIe VGA card instead of the onboard VGA, or by
• decreasing the amount of memory to 2GB

though, here I tried to find some software workaround.

What is wrong?

This BIOS returns an incorrect SMAP information which has an overlap area during a free area (100000:bfdf0000) and the frame buffer (70000000:10000000).

* bfdf0000 should be 6ff00000

So, we can fix this issue by patching the FreeBSD boot loader to convert the incorrect SMAP information into a correct one which hasn't any overlapping area.

How to patch and rebuild the boot loader

To patch and rebuild the FreeBSD boot loader, first of all, you have to decrease the RAM to 2GB because you have to make FreeBSD work properly. After that you can patch the source tree like the following.

$ mkdir ~/Sources
$ cd ~/Sources
$ wget http://miko.org/~tatyana/tech/FreeBSD/FreeBSD_8.2_GA-E7AUM-DS2H_Over2GB.diff
$ openssl rmd160 FreeBSD_8.2_GA-E7AUM-DS2H_Over2GB.diff
RIPEMD160(FreeBSD_8.2_GA-E7AUM-DS2H_Over2GB.diff)= 522615669719b4cac3a0f6a838fefdc00a93bcdb
$ cd /usr/src
$ sudo patch -p0 < ~/Sources/FreeBSD_8.2_GA-E7AUM-DS2H_Over2GB.diff

After the patching, try to build and install the boot loader.

$ cd /usr/src/sys/boot
$ sudo make clean
$ sudo make obj
$ sudo make depend
$ sudo make
$ cd i386/loader
$ sudo make install
$ cd ../..
$ sudo make clean

That's it! ;-)

Thanks

Thanks to adidasprince's Chameleon patch.

return