Installing ESXi 8 on old CPUs

Boot from USB in normal way.

At the initial ESXi Boot menu, press SHIFT-O (letter o)

Type: <space>allowlegacycpu=true and hit enter

Now, although you’ll be prompted during the install that the CPU is unsupported, it will let you continue.

Note – ESXi 8.0.2 will fail to install if your CPU is from pre 2012 era.