TPS61230A: Power rail considerations

Part Number: TPS61230A

Tool/software:

Dear TI Support,
we're designing a power supply circuit that has:
- input voltage 3.6V
- selectable output voltage: 3.6V or 3.9V
The 3.9V comes from a TPS61230A, the 3.6V comes from an high side mosfet.
This is the final circuit:

Considering that the 2 rails cannot be simultaneously switched on (due to the negation of the enable signal), if we attach the high side mosfet output to the dc-dc output, what can happen?
Is this solution advisable or are there better ways?

Thank you in advance for the answer.

Best Regards,
M