I tried to update to today's current build with a Viewpoint intensive WPS running on a Sansa e260. Rockbox utility completed "Successfully", bootloader flashed up, and then a Loading screen came up and froze.
Loaded a back-up, tried again, same problem.
Loaded a back-up again, changed to a simple WPS, update worked but, when I tried to switch back to the Viewport WPS, crash.