Hi,
just for share my experience.
2 days ago, i uploaded via midi into my shruthi a wrong firmware (too big). So this broke my shruthi (no sound, white screen) and it was impossible to upload another firmware (power up holding S6 button didn’t nothing). Damn!
Today after several tries, i succeeded to repair my shruthi burning firmware with an arduino uno.
First i turned arduino as an ISP Programer by uploading sketch “ArduinoISP” which can be find in Arduino IDE.
Second, I wired arduino and shruthi by the shruthi ISP port (i used 3,3V not 5V)
Third, I launched the command “avrdude -p m644p -c avrisp -P /dev/ttyACM0 -b 19200 -U flash:w:muboot.hex:i -U flash:w:shruthi1_1.02.hex:i -F”
Awesome day for me 
My configuration
- ubuntu 14.04
- shruthi-1
- arduino uno R3
- arduino ide 1.6.7
- avrdude 6.0.1