The fix in
http://code.google.com/p/pharo/issues/detail?id=4186

now one thing left:
�we need to get rid of hanging methods with corrupted trailers.

And we do it like this:

(CompiledMethod allInstances select: [:m |
� � � �m isInstalled not and: [ m trailer kind = #VarLengthSourcePointer ]]
) do: [:each |
� � � �each at: each size put: 0 ]

This will replace a corrupted trailer with empty one.