The default ethosu_firmware in github reconfigures the uart2 to be used as
debug port. Those pins are used to manage the HW flow control for the Bluetooth
chip.
Build a custom ethosu_firmware that does not reconfigure the uart2 pins.
Compiled from internal "ethos_u_firmware.git" repository on Stash,
with revision 48a4b9e6a0770212aac529fb7f81ed2e6ff51cbd
md5sum: 0bf8686fcabec7378483755106dc6433
https://onedigi.atlassian.net/browse/DEL-8587
Signed-off-by: Isaac Hermida <isaac.hermida@digi.com>