I can confirm that this hack works with a bone stock Rigol DL3021 as well.
I used the exact same USB stick as I did on my DP832
By default the LAN interface is an additional option you'll have to purchase. I ended up applying the hack using the RS232 interface.
I didn't bother installing Ultra Sigma, so I just used an ASCII based serial monitor instead.
Default baud rate: 9600, 8 data bits, 1 stop bit, no parity, no hardware handshake
Just remember that you need to add CR LF as line ending
:PROJ:SET MODEL,DL3021A
After the hack was applied all options where now available.
Are there any devices left that this hack would possibly work on?