Below is a brief description of how I got my integrated S3 unichrome graphics working properly on R5F27. fyi this particular build has an ECS P4m800prom motherboard.
It is not a work of my skills but a collection of information consolidated...hopefully to help someone in a similar situation. In other words I stole the parts from someone on this forum and from someone elsewhere and compiled them here for you..and me when I rebuild it and forget this.
First I realized I received the black screen after the text "Checking Nvidia installation"
A lot of people have this issue when using the 350 TV out but I do not have a PVR350.
I had to download and install the openchrome drivers. Then I had to move the drivers from their default install directory to the proper one and I had to quickly edit the xorg.conf to reflect the proper driver.
From my notes.
update the unichrome driver ... (both drivers)
$ cd /tmp
$ mkdir openchrome
$ cd openchrome
$ svn co http://svn.openchrome.org/svn/trunk
$ cd trunk
$ ./autogen.sh
$ make
$ make install
# cp /usr/local/lib/xorg/modules/drivers/openchrome_drv.so /usr/lib/xorg/modules/drivers/openchrome_drv.so
# cp /usr/local/lib/xorg/modules/drivers/openchrome_drv.la /usr/lib/xorg/modules/drivers/openchrome_drv.la
nano /etc/X11/xorg.conf
find the driver for the video card and change it to openchrome
#reboot
Hope this saves someone some trouble. have fun