FYI, I just upgraded sparc64 and i386 boxes from 1.6_BETA1 to
1.6_BETA3 via sysinst on serial console.

All went well in both cases.  

Only nit is that sysinst does quite a few full screen repaints - some
pages (noticably the return to the main menu) involve several
refreshes.  On an xterm each of these repaint results in flipping
to/from the alternate memory page (or whatever its called) which
results in a very noticable flashing effect at 9600bps.

--sjg