A HUGE thanks to tv84 for helping me with my DG812->DG992 upgrade!
I've written up a set of instructions based on tv84's original instructions, but also added a few bits gleaned from other discussions and my own adventures and missteps while performing the upgrade. I have not tried the upgrade method for firmware 01.09, so the command I've listed for that upgrade is based only on what I've read in this forum. I would definitely appreciate any comments, suggestions, additions, or corrections to what I've written here.
HOW TO CHANGE RIGOL DG800/DG900 MODELS
1. Format a blank USB disk of at least 1GB capacity as a FAT32 drive
2. Write the special signature to the USB disk (assuming it is at /dev/sda1) with the following Linux command:
sudo dd if=DG800_sardinha.bin of=/dev/sda1 bs=512 seek=2000000
Or use the HxD program in Windows to write the following 8 bytes at offset 2000000:
0B0A3B2E5F4CECBE
3. With the special USB disk inserted, send the SCPI command via the DG USB interface (using Rigol Ultra Sigma, for example) to change the model to DG992:
:PROJ:MODE DG992 (for firmware 00.01.08.00.01 or lower)
:PROJ:MODIF DG992 (for firmware 00.01.09.00.00 or greater)
DO NOT use the "Send and Read" command. Attempting to read a response from the DG will invalidate the command.
Possible model types (as seen in the first 4 bytes of the sd.xx configuration file):
00 - DG811
01 - DG821
02 - DG831
03 - DG812
04 - DG822
05 - DG832
06 - DG952
07 - DG972
08 - DG992
4. Remove the special USB disk from the DG and restart the DG.
5. Enjoy!