One afterthought to my above post;
If you are unable to force the unit into bootloader mode from the menus you may have to short out a jumper on the main PCB. Here is a table of the various board types and the location of the jumper. Ensure the unit is not powered up before shorting the jumper.
After the jumper has been shorted, the unit will start in bootloader mode allowing you to perform your terminal level commands. Once you have finished, power the unit down, remove the jumper and then power the unit up again.
PCB JUMPER SETTING LOCATIONS
Product Product Cat Board PPS Boot hold
DIGITAL SPRITE DS01 DVT37 25 J3
DIGITAL SPRITE 2 DS2 DVT37 25 J3
DS2A DVU42 50 J1
DVU52 50 J1
DS2A 4 WAY DVU54 50 J1
DS2A 6 WAY DVU55 50 J1
DIGITAL SPRITE PLUS DS2P DVX12 100 J1
DS2P 6 WAY DVX13 100 J1
EC04 D4C CREAM D4C21 25 J2
EC04 D4C CREAM D4D2 25 J4