sfdisk /dev/hdb -O hdb-partition-sectors.save
Checking that no-one is using this disk right now ...
OK

Disk /dev/hdb: 77545 cylinders, 16 heads, 63 sectors/track
Old situation:
Warning: The partition table looks like it was made
  for C/H/S=*/255/63 (instead of 77545/16/63).
For this listing I'll assume that geometry.
Units = cylinders of 8225280 bytes, blocks of 1024 bytes, counting from 0

   Device Boot Start     End   #cyls    #blocks   Id  System
/dev/hdb1          0+   4864    4865-  39078081    c  W95 FAT32 (LBA)
/dev/hdb2          0       -       0          0    0  Empty
/dev/hdb3          0       -       0          0    0  Empty
/dev/hdb4          0       -       0          0    0  Empty
Input in the following format; absent fields get a default value.
<start> <size> <type [E,S,L,X,hex]> <bootable [-,*]> <c,h,s> <c,h,s>
Usually you only need to specify <start> and <size> (and perhaps <type>).

/dev/hdb1 :