i tried to update shurti from 0.91 to 0.94 using midiox.
it failed and now my shurti is stucked
i have that blank screen and 4 leds lite. when i send sysex from midiox shurti leds goes OFF.
and nothing happen :S
here are the settings i use to update the tempest(DSI) firmware successfully.
low level input buffers Size256 / Num 32
low level output buffers Size 3000 / 256
Be sure to use the Electro software with the SYSEX file, and not the MIDI file (i know, once written like here it seems obvious, but i a m quite slow and tried with the .mid file without luck :P)
I had the same problem, using a cheap usbmidi. when I tried again with my amt8, everything was fine.
also, try higher ms settings in midiox. for me, 300 ms and above worked.