Unfortunately, we do not have a Novatech nTab II device at our disposal and are unable to test, reproduce, and troubleshoot your issue locally. Therefore, we can only suggest possible workarounds.
If the adb command prompt does not list your device, then it is not properly installed and recognized by your system.
Did you install a device-specific driver (an OEM one, or a third-party one) or did you try installing an universal ADB driver? (With the fragmentation of the Android market, it is usually the driver that causes issues with Graphite.)
Another issue that you might be facing is having some sort of device management software that uses its own instance of adb.exe. If this software is running along with Graphite, conflicts might arise between Graphite's adb and the other adb process. If this is the case, close Graphite, run Task Manager to kill any adb/device management processes, and run Graphite again. And finally, make sure that you are not running the Icenium extension for Visual Studio and Graphite simultaneously.
About your second question - it is usually a matter of setting up permissions (usually disabling SMS or Telephony) to make an Android app compatible with tablets. When configuring the permissions in Project Properties and in the configuration files, keep in mind that the enabled Apache Cordova core plugins might add their own required permissions during the build process. So, always make sure to disable the core plugins that you do not need.
And last but not least, check if your app is configured to run on devices with the screen density of your Novatech tablet and make sure that your hardware acceleration settings comply with the specification of the tablet.
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