Quote Originally Posted by sudodus View Post
@marks2,

Instead of fighting with a persistent live system, you can try to create an installed system in a fast USB 3 pendrive or an SSD connected via USB 3 or eSATA. This way you will get a system, where is it possible (maybe even easy) to install the Intel microcode, that you want. I am running such systems successfully, and I find them stable.

See this link with details to help with the installation: How do I install Ubuntu to a USB key? - install like into an internal drive
I've done this as well, installed to a generic USB3 flash drive. It seems to work fine though it's slower than installing to a HDD or SDD. My machine having USB2 ports didn't help anything, I'm sure. I can't comment about durability, i haven't used it that much. it used to be recommended to use an ext2 file system to reduce writes (no journal) but I've also read that the latest iterations of of ext4 don't produce much more flash wear than ext2. Just take your time and put the bootloader on the correct drive.