The A590IS won't boot with trunk-5071, the print led button blinks.
I went back to trunk-5069 and it all works fine,
except that it won't show Build Info - Revision from the chdk menu, it shows a zero.
The changes from 5069 to 5071 should only affect comments in stubs_entry2.S for digic 6 cameras and the ND define for sx260hs, so I'm at a loss as to how this could break A590. Other candidates might include an install problem or SD card issue.
Are you building yourself, or using autobuilds?
The zero revision is expected if you aren't building from and SVN working copy or the working copy is incompatible with the 'svnversion' tool on the path.