Solution:

The PCA-6154 BIOS rev.1.11 does a little different to others. If you use on board VGA then the memory section C000h to CB00h will be occupyed by the decompress VGA BIOS. The system BIOS will be decompressed to the F000h to FFFFh sigment. The memory sigment form CC00h to EFFFh is free to use. I had check with R&D engineer and use AMIDIAG rev. 5.11 test to proof. A important thing is that if you plug in a VGA card, BIOS will release C800h to CBFF out. This means the SiS 5598 neeed to use this sigment. So if your customer need to use C800h to CC00h. Please plug in a CPU card (I use PCA-6653).