As to change the partition layout of the nand disk, we have to create the pit file ourself for custom partitions size. The pit file can be obtained by compiling a C file containing the partition info. Below shows part of the s1_odin_20100512.c provided by coolya

* /dev/block/stl1 - 6 omitted

{ 0, 0, 0x06, 0x00, 0, 256, 30, "", "KERNEL", "zImage"},
{ 0, 0, 0x07, 0x00, 0, 256, 30, "", "RECOVERY", "zImage"},
{ 0, 0, 0x16, 0x02, 0, 256, 1146, "", "FACTORYFS", "factoryfs.rfs"},
{ 0, 0, 0x17, 0x02, 0, 256, 536, "", "DBDATAFS", "dbdata.rfs"},
{ 0, 0, 0x18, 0x02, 0, 256, 140, "", "CACHE", "cache.rfs"},
{ 0, 0, 0x0b, 0x00, 0, 256, 50, "", "MODEM", "modem.bin"},

The first entry is mapped as /dev/block/stl7 (/dev/block/bml7), and so forth. Thus MODEM will be mapped to /dev/block/stl12 (/dev/block/bml12). For the meaning of each of the column above, we have to refer to the structure listed below from the C file:

unsigned int _00; /* unknown. set to 1 is entry unused */
unsigned int _04; /* unknown. set to 1 is entry unused */
unsigned int partid; /* partition ID */
unsigned int flags; /* flags. 0x 00= RO, 0x02=R/W */
unsigned int _14; /* unknown */
unsigned int blocksize; /* blocksize in 512 byte units */
unsigned int partsize; /* partition size in blocks */
char _20[8]; /* unknown */
char partname[32]; /* partition name */
char filename[64]; /* filename */

Take the CACHE partition as example, the partition info stated in s1_odin_20100512.c reads:

{ 0, 0, 0x18, 0x02, 0, 256, 140, "", "CACHE", "cache.rfs"}

That is to say, the properties of the CACHE partition should be, starts from column one:
0 - the partition is being used
0 - the partition is being used
0x18 - the partition ID
0x02 - the partition allows read/write
0 - (unknown)
256 - blocksize
140 - partition size
"empty" - (unknown)
CACHE - the partition is known as CACHE
cache.rfs - the file to be filled


Normally, we only need to deal with columns 1, 2, 4, 7, 9 and 10:
- column 1 and 2: set to 0 to mark this partition usable
- column 4: set to 0x02 for both read/write accesses
- column 7: set this to 140 units (or 35MB) for this partition, where 140 x 256 / 1024 = 35MB, ie each unit = 0.25MB
- column 9: set this as CACHE for internal reference
- column 10: set the filename required for filling this partition

So for the KERNEL or /dev/block/stl7 (/dev/block/bm7):

{ 0, 0, 0x06, 0x00, 0, 256, 30, "", "KERNEL", "zImage"}

means that this partition is known as KERNEL, with 7.5MB disk space allocated, and the required file is zImage



read more:
Free more available disk space from NAND - PART I
freeNANDmod - get more space from NAND - PART III
freeNANDmod - get more space from NAND - PART IV