I have four Viola carrier board (not the plus model) and even when a battery is inserted the hardware clock will restart a 0. Saving with hwclock -w -f /dev/rtc1 works, reading after gives the right time. but after a cold boot time is lost. On Viola plus using rtc0 this did not happened but since out of stock we got some std model. The datasheet sais that the colibri RTC is powered on this model. Any clue as why time is lost and anyway to solve this
You probably suffer from Viola Carrier Board Errata#1.