hwclock (5) - Linux Manuals
hwclock: settings that affect the behaviour of the hwclock init script
hwclock - settings that affect the behaviour of the hwclock init script
DESCRIPTIONThe /etc/default/hwclock file contains settings in POSIX format:
Only one assignment is allowed per line. Comments (starting with '#') are also allowed.
SETTINGSThe following settings can be set.
The hardware clock device you want to use. Defaults to rtc0.
It should probably match the CONFIG_RTC_HCTOSYS_DEVICE kernel config
If you change this, you also need to install a custom udev rule, mirroring /usr/lib/udev/rules.d/85-hwclock.rules. Otherwise, the hardware clock device will be ignored during boot.
On almost all systems, this should not be changed.
On systems using systemd as init, the hwclock init script is ignored.