Just thought I let you know, you can use Dingleberry(Windows.v3.3.3) to downgrade from 10.0.6.386 to 10.0.4.197.
In the Dingleberry-3.3.3-Windows\Firmware folder, create a folder called 2.0.0.4869.
Dump your 10.0 bar file in newly created folder and rename to cfm.os.com.qnx.coreos.qcfm.os.sdk.4869.79475.signe d.bar
Now you can use Dingleberry(In Development Mode) to upload your OS.
I did it as an experiment, no particular gain with software, but maybe someone can use this info.
EDIT :
You can also use this process to upgarde from 10.0.4.197 to 10.0.6.386.