Hey hi Karthik,
are you still facing the same issue?
I was also facing this issue while flashing .axf from MCUXpresso IDE.
I tried through many ways and found the actual problem!
It was because of spacing in the path of the project! (Folder name with spaces)
To check whether you have the same problem or not, just copy your .axf to somewhere else where there is no spacing in the path and flash.
It worked for me!
Regards,
Prashant Humbre