Have you rebooted, tried anything else?
I do not care for the blue, but this red is not an improvement.
I rebooted, hard powered cycle, unplugged cable. Nothing.
This was caused by me powering off the P15 (I powered off the DS before turn P15 off) to move some cable around.
I just did the exactly thing again and it fixed it… powered off and on through the P15. Very strange! there’s seem to be some affect that P15 is inducing on the DS.
Strange indeed, although it may have nothing to do with the P15 - unless it reappears only when powered by the P15.