I just received my Rasclock V4, and set it up according to Afterthought's instructions. Seeing as I'm doing this on a RPi B+, with the latest raspbian image downloaded from raspberrypi.org just yesterday I assumed i could use the instructions for new firmware (just enabling the dtoverlay).

All of this seems to work. the hwclock command seems to respond normally (no errors, time is set and read correctly).

When I reboot or shut down the RPi however, the time is all wrong when it comes back up. With fake-hwclock still in place, it showed a difference of the reboot-time (or duration of shutdown) and with fake-hwclock removed, it initializes on the UNIX epoch.

I verified the battery is good. It's brand new out of the blister, and reads 3.17V.

Further troubleshooting led me to trying other installation methods, all succesful when powered on, but the same result after reboots or shutdowns. I2C however does work, and the rasclock is detected using i2cdetect.

Is my Rasclock faulty, or did I still do something wrong?

2 Answers 2


I contacted Afterthought last week with this problem, and today they supplied the anwser! I have tested this, and can confirm this works.

Hi Jeroen,

There seems to have been a change to Raspbian. Our tests suggest that if you edit the file /lib/udev/hwclock-set and change --systz to --hctosys then it works ok.

Thanks, Andy Duller


I know it would not help you directly, but I have exactly the same problem. Some days ago I did under Raspbian apt-get update and apt-get upgrade. My model is also RPI B+ und RasClock is v4.0. I measured the voltage on the RasClock board and it seemed to be OK. The hwclock is also reponding and time setting works well. I also use dtoverlay. After deleting fake-hwclock and then after restart RPi the time is 1.1.1970. System time (using 'date' command) and 'hwclock -r' has the same time. So in total same behavior. I think the hwclock simply forgets its time and answers during boot process with the primary setting of manufaturing.

Additionally I exchanged the RPi itselve (also B+ type) the same RasClock and the same sd-card. It happend the same.

I had the same problem with a RasComm board, there was a production problem, because the buffer battery was nearly empty after one day. Conrad electronic sent me 3 different boards with the same effect so I decides to try the RasClock :(


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