Debian-Pi-Aarch64/docs/ds3231-rtc.md

RTC Mod DS3231 Readme

1. Change to user root:

sudo -i

2. Disable Fake-Hwclock Service:

systemctl mask fake-hwclock.service

3. Copy boot kernel:

cd /boot/
cp /boot/EFI/BOOT/bootaa64.efi  ./kernel8.img

4. Edit file: /boot/config.txt

Change

...

## RPI AARCH64 BOOT CORE CONF ##
arm_64bit=1
arm_control=0x200 
armstub=RPI_EFI.fd 
disable_commandline_tags=2 
device_tree_address=0x8000 
device_tree_end=0x10000 
device_tree=bcm2710-rpi-3-b-plus.dtb
hdmi_force_hotplug=1
force_turbo=1
initial_turbo=30
disable_splash=1
boot_delay=1
dtparam=random=on
##   Do not change above !!   ##

...

To:

...

## RPI AARCH64 BOOT CORE CONF ##
arm_64bit=1
arm_control=0x200
#armstub=RPI_EFI.fd
kernel=kernel8.img
#disable_commandline_tags=2
#device_tree_address=0x8000
#device_tree_end=0x10000
device_tree=bcm2710-rpi-3-b-plus.dtb
force_turbo=1
initial_turbo=30
disable_splash=1
boot_delay=1
dtparam=random=on

dtoverlay=i2c-rtc,ds3231

##   Do not change above !!   ##

...

5. Edit file: /boot/rc-local

Before " exit 0 ", add content bellow:

# read rtc-time
hwclock -r

# write rtc-time to system
hwclock -s

exit 0