I have below in /mnt/sda1/opt/bootlocal.sh:
sudo sed -i 's|\\u@\\h:\\w|\\e[91m\\u@\\h:\\w\\e[39m|' /home/*/.profile
Its working (If using SmartTTY) while login to username tc, Im not sure about other username though,
but from my local VMware Workstation console, the PS1 its not working, still default even I put in bootsync.sh