Heres an idea… A gps dongle can be had for around a tenner these days an the gps signal contains the time. It shouldn"t be that hard to write a script to be called once the gps had grabbed the time to then set the system clock. I know it"s not as reliable as a proper rtc but useful an easy to implement, with the added benefit of have GPS for other uses too.
That would be a neat solution, providing the dongle can "see" the satellites (i.e. you might need a long USB lead to hang the dongle out of a window during the boot sequence.)
One of the problems of not having an RTC is that time-stamping can get all in a dither – newer files and entries in system logs etc. have earlier dates than older ones, etc.
I don"t know how long it would take a GPS dongle to acquire the satellites and update the system time, but it could be several minutes. It would probably be better to wait for that to happen before any files were updated.
A partial soluition to that may be to periodically (say 20 seconds )save the current time to a file. When the system boots, it reads that file, and adds (say) 30 seconds on, to give a unique and incrementing time-stamp, then picks up the GPS time as soon as it is available.
Latest Debian we are using here at Broadcom does something similar - it reads the last log message and uses the time from that.
GPS dongles do work - got one running on a Raspi this week.
Principal Software Engineer at Raspberry Pi (Trading) Ltd.
Contrary to popular belief, humorous signatures are allowed. Here's an example...
"My grief counseller just died, luckily, he was so good, I didn't care."