Galaxy S GT-I9000: how to fix boot to recovery with Volume up+Power?
OK. I found the correct combination. It seems that the recovery distributed with Cyanogenmod 10 M2 for galaxysmtd is really picky about the hardware buttons.

Here's how you can boot to recovery:


Start with Galaxy S powered off
Press and hold Volume up + Home
Press and hold Power button
Wait for (factory default) Galaxy S GT-I9000 boot display to show up
Release the Power button before the second boot display with text "Cyanogen(mod)" shows up. Keep holding the Volume up + Home buttons.
Wait for Recovery to start. After you see the recovery menu, you can release the Volume up and Home buttons.


If you fail to release the power button before the second boot display, you cannot get it to go into the recovery mode. Instead it will enter the normal boot sequence which seems to fail if you keep holding the Power button. On the other hand, if you don't keep buttons pressed long enough, it will enter the normal boot sequence, again. I haven't figured out if holding the Home button is really required but at least it does not prevent entering the recovery mode.