+1 Dell Latitude D820 SLIC 2.1 mod. Testing and appears working ok. What I would advise is update to the latest official BIOS before running the mod. I had issues with an older installed BIOS, where it failed to update correctly. Updating to A09 (latest version) and then running the mod,no issues at all. Windows flasher took about 2-3mins to reboot laptop.
I tried to flash back to A15, and it became SLIC 2.0 -- a big progress at least. Reboot and flash the 2.1 in dos, it upgrades to A17, but still cannot get activated.
For n-series, you probably need to use ASSET.COM manufacturing mode reset trick to get it to "normal". That worked for some machines to get SLIC turned back on.