The various Raspberry Pi RTC guides I've read instruct the user to disable/uninstall fake-hwclock and then tweak /lib/udev/hwclock-set so that it runs `/sbin/hwclock --rtc=$dev --hctosys` (but not `/sbin/hwclock --rtc=$dev --systz`). Whether these instructions are valid and correct—and for which versions of Raspbian prior to Trixie—is unclear to me.Why tweak /lib/udev/hwclock-set ?
On other distributions, the kernel (or SystemD) will set the system time from the hardware clock at boot (which is why this script has the conditional `exit 0` at the top). I haven't dug into it but presumably the default mechanisms don't play nice with i2c-rtc, or perhaps the normal behavior has been patched out in Raspbian?
Statistics: Posted by bambinone — Mon Jul 28, 2025 8:13 pm