/diskdump -r /dev/disk2 bootpartition.bin
diskdump v0.1 - (C) Dave Chapman 2005
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

[INFO] Reading partition table...
Bad boot sector signature
Part    Type   Start Sector    End Sector    Size (MB)
   0    0x90     -1073744064    2147479335     1572862
   1    0xbf           9412    -1073734653     1572862
   2    0xfe     -1881115580    -1881100621           7
   3    0x00     -2139062144    -2139062145           0
[INFO] Seeking to sector -1073744064
[WARN] Seek error - reading -1073744064 sectors instead