Today I tried to fix an old issue with an old laptop having dual boot - windows / ubuntu. This issue occurred one day out of nowhere (someone from forums said it was caused by a windows update).

While the windows system still boots, the laptop cannot boot into ubuntu and always gets stuck at a grub …

This post is a revised version of link.

The following steps should be followed:

1. Edit the file /etc/dnsmasq.conf on your router, and update the mac address associated with the intended ip address.

   dhcp-host=<mac address>,<ip address>
   

2. Stop dnsmasq service

   sudo systemctl stop …

Here are the steps for configuring a DHCP server in a local network.

Set static IP to the second network card enp9s3 (this name can be different on a different PC) on the DHCP server PC. Run

 sudo vi /etc/network/interfaces

Edit the file according to this sample:

# interfaces(5) file used by ifup(8) …