When I bought my first HW, I thought setting Daylight Saving "on" made it automatically adjust and "off" was only for areas that remain on standard time year-round. But of course, that fall, it turned out I was wrong - you have to turn it "on" and "off" yourself every time DST goes into or out of effect.
(BTW, I actually have a clock/radio that works the same way. You don't have to change the time manually, which was always a mess on those old clocks, but you do have to switch DST on/off manually!)
OTOH, considering the mess other devices such as the DTVPal have made of DST, and given the evident lack of competency of the MStar firmware developers, perhaps a manual setting is better than the alternative. Otherwise, we might have HW's that changed over in April and October!