I dug into this a little deeper today as it gave me an opportunity to 
study ImageSegments. I extracted the cs from 001 and used a binary 
editor to search for version number. I found one sequence 16r64006619 
which decodes to a big-endian 6502 ImageSegment. In 002, I found the 
sequence 16r66190073 which decodes to a little-endian segment.

When I dropped 001 pr into Squeak 5.2alpha (18120/64b/Ubuntu) and 
examined the resulting error stack I found something strange.

Before the endian check in LegacyImageSegment>>#comeFullyUpOnReload, the 
instance is already created in DataStream>>#next method assuming 
little-endian, so segment ivar first word is 16r66190064. Therefore, the 
endianness check in:

ImageSegment>>endianness
... ^(segment first bitShift: -24) asCharacter == $d ifTrue: [#big] 
ifFalse: [#little]

ends up checking the wrong byte for  endianness. I changed this code to 
check for both $s and $d and confirmed that endian check is incorrect at 
this point.

I got stuck here. How should one fix this error?

Regards .. Subbu