Timed out waiting for device dev-ttyS0.device

If you see this “Timed out waiting for device dev-ttyS0.device” during boot up make sure that CONFIG_FHANDLE is enabled in kernel config

Scrip to check if FHANDLE is enabled

#!/bin/bash
TEMP=`gunzip -c /proc/config.gz | grep CONFIG_FHANDLE | wc -l` 
if [ ${TEMP} -eq 1 ] 
then 
 echo "FHANDLE enabled"
else 
 echo "FHANDLE not enabled" 
fi

If FHANDLE is not enabled, recompile the kernel with CONFIG_FHANDLE=y

Newer versions of systemd requires a kernel with FHANDLE enabled