How to handle system update with a MBR disk?

Hi, I would like to know how to properly update a system with MBR boot record. Because normal system update shows an error advising me to convert my system to GPT. Problem: My Acer M6610G doesn't support UEFI/GPT boot drives. I figured out two ways to update my machine.

1. For every update Apple released I had to crate a bootable USB device and update using that.

2. Convert my system drive to GPT and connect a MBR USB drive with clover.

I think there should be an easier way to do this? How do you update your older MBR machines?

Thanks four your help