UEFI is the unified extensible firmware interface (aka BIOS) on newer systems.
https://en.wikipedia.org/wiki/Unified_Ex..._Interface
Dual-boot or multi-boot is running more than one OS at a time on a system switchable at boot time.
https://en.wikipedia.org/wiki/Multi-booting
Looks like your trying to upgrade a persistent USB install media (rescue USB).
This is not possible as the OS portion is still written to the media as a read only file system.
Only the user data (AKA home directories, etc.) are stored on the persistent FS.
https://en.wikipedia.org/wiki/Unified_Ex..._Interface
Dual-boot or multi-boot is running more than one OS at a time on a system switchable at boot time.
https://en.wikipedia.org/wiki/Multi-booting
Looks like your trying to upgrade a persistent USB install media (rescue USB).
This is not possible as the OS portion is still written to the media as a read only file system.
Only the user data (AKA home directories, etc.) are stored on the persistent FS.
