Format of the SPF DIF file (SGHFD v0.60):

0000h 0020h Header
0020h ???? Block data (plain for SPFD, ZLib-compressed for SPFZ)

Header:

0000h 0004h 'SPFD' or 'SPFZ' signature
0004h 0004h ASCII Phone ID
0008h 0010h ASCIIZ (00h) right-padded software ID
0018h 0004h Reserved
001Ch 0004h Number of blocks in block data area

Block:

0000h 000Ch Block header
000Ch ???? Data

Block header:

0000h 0004h 'FBLK' signature
0004h 0004h Block type
0008h 0004h Block size

Common dIFC type block data:
0000h ???? RTF comment

SGHA class NORD/nOrR type block data:

0000h 0004h Starting address in NOR flash
0004h ???? NOR data

SGHA class TFSF type block data:

0000h 0004h Filename length
0004h ???? Full TFS filename
???? ???? TFS file data

Comments:

1. Phone ID is phone class ID. If SGHFD (or other software) does not know
how to process phone class specified, it must display an error and stop
processing. You can not intermix multiple phone classes in one DIF file.

Phone classes currently known by SGHFD:
'SGHA': Samsung X100/X600/E100/E700/S500/E800 series phones
(Nucleus Plus RTOS).

2. Software ID must be right-padded by zeros up to 16 bytes length.
It is given just for informational purposes and is not processed
by SGHFD in any way.

Examples:
'X100XEDG1', 0, 0, 0, 0, 0, 0, 0.
'AUTODIFF TOOL', 0, 0, 0

3. Block naming conventions:

First block name letter defines 'mandatory' block if it is capital and
'optional' block if it is small. If the first letter is capital and
SGHFD (or other software) does not know how to parse that block, it
must stop parsing here and display an error message. If the first
letter is small and software does not know how to parse it, it must
skip and ignore that block.

Second block name letter defines 'author' block if it is capital and
'third-party' block if it is small. 'Author' blocks are blocks defined
by the author of SGHFD. If you want to make your own private block
extension to DIF, you must keep second letter small to ensure it will
not conflict with future SGHFD versions.

Third block name letter defines 'safe to copy' block if it is capital
and 'unsafe to copy' block if it is small. When processing DIF file
to include it into other DIF file, or when modifying DIF file someway,
blocks marked with small third letter ('unsafe to copy' blocks) which
are not known by the processing software must not be processed, and must
be thrown out.

Common blocks currently known by SGHFD:
'dIFC' - DIF comment in RTF (Rich Text Format), multiple dIFC
blocks are joined by SGHFD into single comment

Blocks known by SGHFD for 'SGHA' class phones:
'NORD' - NOR flash data
'nOrR' - NOR reversal (undo) data
'TFSF' - TFS file

4. Starting address in the is the linear address in phone flash.

5. For 'SGHA' class phones, internal NOR flash blocks have 10000h
bytes granularity (not all the blocks, really, but the flasher emulates
10000h granularity where needed). If the NOR block being written is not
granular on start/end, remaining granularity unit data will be read from
the phone itself at the flashing stage. This makes patching a few bytes
pretty easy.

6. 'SPFZ' files are generic SPF DIF files where the block data itself is
compressed with ZLib as a single datastream.