Symptom
In some circumstances, when the switch is in the loader> prompt, booting from USB fails.
Conditions
Let say the leaf switch is active and is running on version X. For some reason it goes to the loader> prompt. If from the loader prompt, you boot from USB with the version X image, the switch will boot up. However, if you boot the switch from USB with version Y image, the boot fails and afterward booting with version X also fails.
So the condition is:
In the loader prompt, boot the switch from USB with version Y image, while before the switch went to loader it was version X that the leaf switch is running with.
Workaround
1. Boot from a TFTP server.
2. Boot switch from a USB NX-OS image and convert the switch to ACI mode again.
