ShellMapVar

This tool will set the mapvar Shell environment variable to the device mapping the tool is run from.

Usage:

Shell> ShellMapVar.efi
Shell> %mapvar%
fs0:\>

This is primarily interesting for writing robust UEFI Shell startup scripts, since many commands and tools don't work correctly without a mapping and the actual mapping depends on the mappings present.

Example:

ShellMapVar.efi
%mapvar%
load path\to\my\driver.efi