If it's any help to others.....just fixed a problem with one of several 405s I've used (or set up for friends
One of my own 405s suddenly stopped playing mp3s ???!!
It would load them from the Music folder OK but froze the device when I tried to play them. Having tried a "pinhole" reset, and on board factory reset, unit reformat and download of fresh firmware the problem still existed. Everything seemed normal until I transferred in some mp3s and tried to play one...and it would freeze again
In desperation tonight I connected the 405 to my PC and did a PC controlled Scandisk (Which hadn't worked previously) and this time I did a PC controlled reformat of the 405
.....reloaded the firmware .....reset the device time, date and my settings...transferred some mp3s....and lo! ....it's working correctly again
If at first you don't succeed....don't give up !!