A reader of this forum and WP 34S tester (thanks Hubert) was missing the SAM-BA boot function in the latest WP 34S firmware release (only in SVN). He is right, ON+S seems to be gone. Why?
ON+S pressed accidentally by a user without the cable and working SAM-BA software can easily turn his calculator into a battery eating brick without any visible functionality. To make this harder, I decided to hide the ON+S key combo behind another one, ON+D. The latter is primarily used as a debugging aid, disabling all power saving and thus allowing the hardware debugger to work. I just decided to give this mode a double meaning in the sense of allowing some dangerous functions to be selected by the user.
In short: To reflash your calc press ON+D once and then ON+S twice to go into SAM-BA boot mode.
Edited: 26 June 2011, 11:44 a.m.