Factory Test, DUT US009, DUT US0010, with Mini Player Mini MP3 Player Some Times Fails , Factory Test, v0.4.2.3 and v0.4.2.4

[ForrestErickson]

Describe the Failure / Bug
A clear and concise description of what the failure / bug is. Describe the problem NOT the fix.

Short Summary of the expected behavior: Factory Test of UART, Commands 4, 5 and 6 should work.

Short Summary of the buggy behavior:

DUT: US0009 with firmware v0.4.2.3.

Issue command 4
DUT did not report normal UART Mini MP3 player detection.
DUT had No speaker click of reset

Issue command 5
DUT found expected audio files

Issue command 6
DUT played the OK file through speaker

DUT: US0009 with firmware v0.4.2.3.

Issue command 4
DUT did not report normal UART Mini MP3 player detection.
DUT had No speaker click of reset

Issue command 5
DUT found expected audio files

Issue command 6
DUT played the OK file through speaker

DUT: US0010 with Firmware Version: v0.4.2.4

Issue command 4
DUT this time responded to the command
DUT did report normal UART Mini MP3 player detection.
DUT had normal speaker click of reset

Issue command 5
DUT found expected audio files

Issue command 6
DUT played the OK file through speaker

Results

1. There is inconsistent behavior of the Mini MP3 player with the Factory Test firmware. BOTH have at one time or another not responded to the command 4 by not making the reset sound and reporting DFPlayer Not Detected.
2. Note the only difference between Firmware Version: v0.4.2.3 and Firmware Version: v0.4.2.4 is that the volume is set from 20 to 30 to make testing with the 28mm speaker on the test station easier.