Yeah I saw that they have done the table swap for 4020 as well.
By all means test it but to be honest I don't know if its worth the trouble...

There are no new features at 402x and haven't really noticed any speed increases as advertised. However it would be worth changing the partition scheme so that you can swap between versions without losing your maps and music.

JohnC has the cable at the moment so he'll have to write the Dlscript.txt file for you for integrate into the firmware image. He's a busy man but he is always very obliging with requests.