Specifications

192 Version 2.0
Description
This command changes the UEFI variable specified by name and guid. If = is
specified, but data is not, the variable is deleted, if it exists. If = is not specified, then
the current variable contents are displayed. If =data is specified, then the variable’s
value is changed to the value specified by data.
-bs, -rt and –nv are only useful if the variable already exists. If the variable already
exists and the attributes cannot be changed, then -1 is returned.