advice. on sansa clip sport

1. trying to install alternative firmware on subj. The oly one i have found is us212a_demo.fw but the audio product tool
shows err. 53 and dosnt worj
If somebody know any analogs for the audio product tool that help to deal with us212a_demo.fw ?
Is there any alternative firmware for sansa clip sport besides us212a_demo.fw ?

2. Can somebody advise me where i can learn more about drivers and altwrnatice firmware for sansa clip sport?

3. what tools is best to wipe clean flash memory on briked sansa clip sport ? (assyming fdisk and format doesnt work)

p s. sorry if my post is off topic. maybe somebody can nudge me in right direction.

tnx.

 

If you can send me a link for the US212A_DEMO.fw firmware. Then I can send you the app to use that works for the flashing process.