Short step-by-step guide:
- Order the Olimex ARM-USB-OCD JTAG USB interface
- download / install the bfin toolchain (see the famous post on page 163 of the megathread)
- use the MSO's own probe wires (the loose patch wires for the logic probes) to connect the Blackfin's JTAG bus to the OLIMEX interface
(TDI, TDO, TMS, TRST, GND); I didn't bother with the resistor pullups
- Take 3v3 from the SPI connector instead of the JTAG one
- memdump the SDRAM as per the Tirulerbach instructions
- use rigup tool on this memdump
The result is a set of option keys, that can be entered via the scope's front panel
(or, apparently, via Ultra Sigma, I didn't bother with that ...)
So, in short, using the JTAG memdump route, no need to downgrade firmware (which might brick the MSO)
As far as I'm aware, this is the only way to enable the extra features on the latest non-downgradeable MSO's
JTAG interface => sdram memdump => rigup0.1 => enter keys
Good luck!
Marcel