I have not used the BE in far too long, but have used autoexec.bas to load the current date and time from a RTC connected to the BE via I2C. Then it updates the system time & prints the current time and date onscreen. I'll try and dig up the code today if it'd be of interest.
Check out the following github link to two files, AUTOEXEC.BAS & SETRTC.BAS
(I can't figure out how to post code here directly without formatting issues, does anyone have any pointers?)
SETRTC.BAS allows you to set (program) the time into the RTC. Just update the current system time/date as accurately as possible first, because it pulls this data when setting the RTC.
AUTOEXEC.BAS will load the current time from the RTC and set the system clock accordingly.