rsync 2.5.5 on ARM always transmitting whole files

[Pim Zandbergen]

I have an Empeg car MP3 player (http://www.empeg.com) that is
running an embedded version of Linux on a StrongARM CPU.

When using rsync 2.5.5 on Linux/ARM and rsync 2.5.5 on Linux/x86
to transfer mp3 files, it appears file are always transmitted as
a whole, even if only the timestamp differs.

Files are not transmitted if both size and timestamp are equal.
Files are not transmitted if timestamps differ only, and --checksum
is used.
Files are always transmitted, if files at each end differ only
slightly (ie changed id3 tags at the end of the file).

Adding --no-whole-file makes no difference.

I compiled the 2.5.5 version myself, using a linux/x86 hosted
cross-compiler. Yesterday's CVS snapshot does not fix the problem.

A binary version 2.4.6 I found on the web has the same problem.

A binary version 2.3.2 built by debian does not have the problem.
Unfortunately, this version has other problems I will not bother
this forum with.

Using -vvvv, I can see checksums are being calculated, but no
matches are appearant.

Where do I start debugging this problem? Should I be looking
for gcc bugs, or alignment problems or anything else?

Thanks,
Pim