A couple of weeks ago, I posted an article on the subject of upgrading my 2014 Dell XPS 8700 from Linux Mint 18.3 to the current long term support version 20.3. I had hoped to be able to dual boot both versions during the transition but discovered that would be more of a challenge than I was able to take on. I also wanted to convert the boot method from Legacy (MBR) to UEFI (GPT) as well as to update the BIOS firmware to the latest version available from Dell. I am happy to report that, after a number of restless nights, I finally figured it out. After the fact, it all seemed kind of obvious but while I was in the throes of the struggle it did not seem that way to me. Those of you who are accustomed to tearing down and rebuilding machines as a matter of course will not likely have anything to learn from my travails but if there are any others, like myself, who only do a major system upgrade every two or three years, you might find the story of interest. I am planning to write up a detailed account and will make it available for anyone who might be interested but, for now, here is the crux... First, I backed up the old system and home directories from the target drive (/dev/sda), the 500GB SSD that had the old Mint 18.3 install. A long story in itself, that I'll leave for the detailed account. *The tricky bit* - *is to convert the machine from Legacy to UEFI boot just before you install the new OS from the live USB*. On my machine, the boot menu is accessed by hitting "F2" during restart. Once in the boot menu, navigate to the boot tab and change the boot method from "Legacy" to "UEFI". After saving the changes, the machine boots in UEFI mode from the USB (I had previously configured the USB to be the first choice in the boot order). Once the system launched the live version of Mint, I ran the install process and selected the first option to "Erase disk and install Linux Mint". This process, re-formats the primary drive (/dev/sda) from Legacy (MBR) to UEFI (GPT), creating a 500MB, fat32, EFI partition for the boot loader (mounts at /boot/efi) and formats the rest of the drive in a single "ext4" partition for the both system "/" and the "/home" directories. Another time, I might break out the system and home directories into different partitions to facilitate re-installing the OS without have to rebuild my home directory from backups. After all my agonizing, that's all there was to it. My eight year old machine is now running like a top in UEFI mode (boots in less than a minute) and I even managed to re-partition the little 32GB on-board SSD, that came with the system, as a swap partition. Thanks again to John Nash, Scott Murphy and Jean-François for their advice and encouragement. I will try to write up a more detailed account in the next few days and make it available if anyone one is interested.