Hi Omar,
ad 1) SEC tool does not support creation of manufacturing package on command-line. It is supported in GUI only.
ad 2) SEC tool parses the source image and convert to the format, that will be needed on the build. This feature is same for GUI and for the build CLI command.
d 3) Go to https://nxp.com/mcuxpresso/secure and download the SEC tool for Linux. It contains all tools compiled for Linux. Supported operating system version are described in release notes.
Regards,
Marek
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