printf retargetting for nano-specs Cortex M0

With nano-specs I can't get printf statements like this to work where it needs to take in values from a variable.

printf ("Data1 %d\n", data1);

A simpler printf with just characters work ok.

printf ("abc\n");

Per the standard CMSDK setup, I am retargetting the printf to UART. 

Point to note, when not using nano-specs (no specific specs specified) it works ok. I suppose there must be something different with nano-specs.

Running any code with the top statement in RTL simulation will not output anything from the UART.

Appreciate any inputs in this matter. Thanks

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