Armbian 5.4.43: Network is unreachable; Red LED blinking; RNG failure?

[aves]

# I am working on a new installation of Armbian for Rock64, and have been having an inordinate amount of trouble
# I was working and struggling mightily with getting full disk-encryption on the device.
# I now have another, more low-level problem: connecting to the internet.
# I don't know what is causing it, but suspect a random number generator required for ethernet may have stopped functioning.

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# I verified the image I am using is the same one available at this time from:
$ wget https://dl.armbian.com/rock64/Buster_current
$ if [[ `md5sum file_i_used.img | cut -d ' ' -f1` == `md5sum Armbian_20.05.2_Rock64_buster_current_5.4.43.img | cut -d ' ' -f1` ]]; then
    echo MATCH;
    else echo DIFFERENT;
fi
| -> MATCH

# It's md5 checksum:
$ md5sum Armbian_20.05.2_Rock64_buster_current_5.4.43.img | cut -d ' ' -f1
| -> e0202e3887c8784d456eeab6f6ab2b11

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# I discovered the internet connection problem quickly upon trying:
$ sudo apt install (package names)
| -> Could not resolve 'deb.debian.org'
| -> (With lots of other probably-irrelevant information)

# My first thought is to test network connections with ping:
$ ping 9.9.9.9
| -> connect: Network is unreachable
$ ping 192.168.1.254
| -> connect: Network is unreachable

# systemctl --state=failed reveals that haveged.service failed.
# grepping for the reason yields:
$ systemctl --state=failed | grep haveged.service
| -> haveged.service loaded failed failed Entropy daemon using the HAVEGE algorithm

# Checking journald, grepping for the relevant info I found:
$ sudo journalctl -xe | grep ip-config
| -> (...junk information removed...) device (eth0): state change: config -> ip-config (reason 'none', sys-iface-state: 'managed')
| -> (...junk information removed...) device (eth0): state change: ip-config -> failed (reason 'ip-config-unavailable', sys-iface-state: 'managed')

# I also check /var/log/syslog
# grepping for haveged yields:
$ sudo cat /var/log/syslog | grep haveged
| -> (...junk information...) "haveged[776]: haveged: Couldn't initialize HAVEGE rng 9"
| -> (...junk information...) "haveged[776]: haveged starting up"
| -> (...junk information...) "systemd[1]: haveged.service: Main process exited, code=exited, status=1/FAILURE"
| -> (...junk information...) "systemd[1]: haveged.service: Failed with result 'exit-code'."

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# My next thought is to check the interfaces
# eth0 appears to be up:
$ sudo ifconfig
| -> eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
| ->    RX packets 1 bytes 118 (118.9 B)
| ->    TX packets 245 bytes 42062 (41.0 KiB)
# Why not try to stop and restart it?
$ sudo ifdown eth0
| -> ifdown: unknown interface eth0
# It's still there:
$ sudo ifconfig
| -> (eth0 still listed)

# Can I stop and restart the loopback interface?
# I can:
$ sudo ifdown lo
| -> echo $? -> 0
$ sudo ifconfig
| -> (lo not listed)
$ sudo ifup lo
| -> echo $? -> 0
$ sudo ifconfig
| -> (lo listed)

# I add the following lines to both the /etc/network/interfaces and /etc/network/interfaces.default files,
# but nothing changed. This appears to be a pretty basic configuration So I don't know why:
"auto eth0"
"  allow-hotplug eth0"
"  iface eth0 inet dhcp"

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# Something else new that caught my eye is that the board's red LED is blinking in a rhythm suggestive of the human heartbeat.
# I found this page regarding the LED, but that's all, and there's not much indication of what they really mean:
# https://forum.pine64.org/showthread.php?tid=5847

# I definitely don't have any heartbeat sensors attached, and I tried writing the same image to an SD card with the same results:
$ cat /sys/devices/platform/leds/leds/{standby,power}/trigger | egrep -o '\[\w+?\]'
| -> [heartbeat]
| -> [mmc0]

# The led indicating an ethernet cable is blinking normally
# I poked around using commands like the following to try and find ethernet-related LEDs but found nothing suggestive of ethernet:
$ find /sys/devices/platform/leds -type f
| -> nothing interesting
$ find /sys/firmware/devicetree/base/leds -type f
| -> nothing interesting

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# Upon searching duckduckgo some more I find little that appears relevant
# This was one of the few things that looked promising:
# https://raspberrypi.stackexchange.com/qu...face#14107

# So I check the routing table:
$ sudo route -n
| -> Destination    Gateway    Genmask    Flags Metric Ref      Use Iface
| (None listed)

# Attempt to add default gateway manually:
$ sudo route add default gw 192.168.1.254
| -> SIOCADDRT: Network is unreachable

# what would raise error exit code 7?
$ echo $?
| -> 7

# Check routing table again -- nothing changed, still empty:
$ sudo route -n
| -> Destination    Gateway    Genmask    Flags Metric Ref      Use Iface
| (None listed)

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I will post more updates as I continue to work on this problem.
Can anyone help?

[aves]

I solved this problem by switching to the 4.4 kernel, whose md5 checksum is:
dbcaa7903bfddbdb9d199624fbea801f

I don't know why the 5.4 kernel caused this problem, but maybe it is because I am using an older board -- it has year # 2017 printed on the circuit board