IMG PDALL turns off UDMA?

I see some really weird things with UDMA on IDE hard drives. Sometimes
I boot into the maintenance mode do a "hdparm /dev/hda" and UDMA will
be on, other times it says off. Sometimes if I do a "img pdall" it
turns UDMA off.... Is this normal behavior??? VERY weird stuff and im
trying to make sense of it all
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