Yes, Flash0 is the os files, and Flash1 is the registry and one or two other things (like custom backgrounds in 2.0+, and some gps stuff in 2.71+).

If you delete everything in flash0, you will have a nice, shinny brick. The recovery menu is stored in there. I am not sure what else the menu needs in order to run, though.

If you want an simpler way to wipe the flash clean, go back to 1.5, and then upgrade to any other downgrade-able firmware using the official Sony upgraders. They format Flash0 before they write the firmware files. Then just go back to whatever firmware you were using before. I also recomend that you make a backup copy of your Flash1 if you don't want to lose your settings. Just copy everything to the memory stick, and then copy it back when you have to.

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Yes, that is mostly true, however:

Downgrading to 1.50 and upgrading to 3.03 OEA does NOT format FLASH1.

Even restoring default settings does not format it, it only resets some of the data.

SO, if you ever had crud installed to FLASH1, this can clean it out for ya!

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True. If you just want to clean out flash1, there is an easier way. Just corrupt the registry files to get the blue "settings reset" screen. I belive Flash1 is formated in the process, and there is a far less chance of bricking (compaired to downgrading/upgrading) because Flash1 is easy to restore.

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*sigh*, I wish.

See, this was the problem! I was reflashing ALL The time going from one to the other firmwares, and my FLASH1 was kept the same... *sigh*

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