How to disable UDMA for HDD?

Chuck Swiger cswiger at
Thu Aug 12 10:11:32 PDT 2004

Stevan Tiefert wrote:
[ ... ]
> you did not understood what I wanted. I needed a suggestion how to install 
> FreeBSD without UDMA-support. Your suggestion is only useful if the system is 
> running, but that was not the case!

What happens if you configure the BIOS of the system not to use UDMA modes for 
that device?  Most BIOSes will let you control individual devices, so set 
whatever it is to PIO4; otherwise, disable UDMA for everything long enough to 
complete the install, and then tweak things from there.


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