This document contains explanation of some bytes that are stored in the first 4K block of spi flash boot device.

printf '\x00\x00\x00\x00' | dd conv=notrunc bs=1 of=hws.bin seek=80

The listing below is an output of the following commands:

# dd if=/dev/mtdblock0 of=hws bs=4K count=1
# hexdump -ve '"%08_ax    " 1/4 "%08x" "\n"' hws

My comments are prepended with '#' sign.

# address   # data

# size of (commands+padding+crc), 32-bit unsigned integer
00000000    00000600

#
# this is an address(?) that one can also find in the file
# 'toolchain/image-tool/hw_setting.main.txt.d'
# However in that file it's prefixed with tag 'b' (branch or bypass?)
# but here it is just left alone
#
# see also an output of sysparser.pl:
# ``
# muti_bypass_mode_val = ffff
# muti_bypass_addr_val = 8000400
# ``
#
# image-tool reads the text file 'hw_setting.main.txt.d' and translates
# it to the binary file 'hw_setting.main.d'.
#
00000004    0000ffff
00000008    08000400

#
# These are 4 offsets of multi-hws parts (me do not knows what the purpose
# of _multi_ hws)
# see sysparser.pl, function fun_uboot
#
# They are offsets for multi_f00, multi_f01, multi_f02, multi_end data from
# the beginning of the image
# 0x5C4 = 1476 = 1456 (size of multi_main) - 8 bytes (strip bypass) + 28 bytes
# where 28 bytes = 8 bytes (put back bypass) + 4 bytes (size field at the
#     beginning of image) + 4x4 bytes (these addresses: f00, f01, f02, end)
#
# f00, f01, f02 are actually empty in this build
# but the 'end' section contains one write and one poll instructions,
# see 'hw_setting.image.end.d'
#
0000000c    000005c4
00000010    000005c4
00000014    000005c4
00000018    000005c4

#
# see explanation of command codes in
# 'sn9866_series_datasheet_standard_160930.pdf' on the last pages
#
# see explanation of some registers in
# 'sn9866_series_datasheet_with_registers_v1_04.pdf'
#

#
# This is a block of registers located in ITCM memory.
# See Documentation/arm/tcm.txt for the explanation of what is ITCM.
#

#
# I do not know anything about the following two registers
#
0000001c    00000077 # cmd: write
00000020    ffff6094 # arg: register
00000024    00000000 # arg: value

00000028    00000077
0000002c    ffff609c
00000030    00000000

#
# jmp address
# in RAM (VIRTUAL) memory
# see 'toolchain/image-tool/sysparser.pl:579'
#
00000034    00000077
00000038    ffff6090
0000003c    01d00000

#
# load address
# in PHYSICAL memory
# see 'bootloader/u-boot-2011-09/src/common/cmd_update.c'
# see 'toolchain/image-tool/sysparser.pl:579'
# SB_FWIMG_REGISTER <-- put here IMAGE_BEGIN_ADDR
#
# Note that the jump address is just a load address plus 4 (bytes)
# (we need to skip size field in the u-boot image)
#
00000040    00000077
00000044    ffff601c
00000048    11cffffc

#
# u-boot address
# in SERIAL FLASH
#
0000004c    00000077
00000050    ffff60f8
00000054    00003000

#
# u-boot size
# this is a total size of the u-boot partition on SERIAL FLASH
#
00000058    00000077
0000005c    ffff6020
00000060    0007b000

#
# **Documented** registers:
#
00000064    00000077
00000068    98100008
0000006c    00000001
00000070    00000077
00000074    98100000
00000078    00000001
0000007c    00000077
00000080    90900038
00000084    00000006
00000088    00000077
0000008c    90900034
00000090    00000006
00000094    00000077
00000098    90600000
0000009c    8b000500
000000a0    00000077
000000a4    98000000
000000a8    ece180a0
000000ac    00000077
000000b0    98000004
000000b4    80840222
000000b8    00000077
000000bc    9800001c
000000c0    80000014
000000c4    0000006e
000000c8    00100000
000000cc    00000077
000000d0    90300000
000000d4    00000400
000000d8    0000007a
000000dc    90300004
000000e0    00000001
000000e4    00000077
000000e8    90300008
000000ec    020139c2
000000f0    00000077
000000f4    9030000c
000000f8    00c800a1
000000fc    00000077
00000100    90300010
00000104    00040a00
00000108    00000077
0000010c    90300014
00000110    18050202
00000114    00000077
00000118    90300018
0000011c    13060413
00000120    00000077
00000124    9030001c
00000128    00050204
0000012c    00000077
00000130    90300020
00000134    03036dd0
00000138    00000077
0000013c    90300024
00000140    00070600
00000144    00000077
00000148    90300028
0000014c    020d0101
00000150    00000077
00000154    9030002c
00000158    00000006
0000015c    00000077
00000160    90300030
00000164    00002b01
00000168    00000077
0000016c    90300034
00000170    00000c39
00000174    00000077
00000178    90300038
0000017c    00020002
00000180    00000077
00000184    9030003c
00000188    00c80008
0000018c    00000077
00000190    90300040
00000194    0000002f
00000198    00000077
0000019c    90300044
000001a0    03000001
000001a4    00000077
000001a8    90300048
000001ac    00000003
000001b0    0000007a
000001b4    9030004c
000001b8    00000004
000001bc    00000077
000001c0    9030005c
000001c4    000c5200
000001c8    00000077
000001cc    90300060
000001d0    00000002
000001d4    0000007a
000001d8    90300064
000001dc    00000001
000001e0    00000077
000001e4    90300068
000001e8    01000000
000001ec    00000077
000001f0    9030006c
000001f4    00000001
000001f8    0000007a
000001fc    90300070
00000200    00000002
00000204    00000077
00000208    90300078
0000020c    0a010101
00000210    00000077
00000214    9030007c
00000218    0101ffff
0000021c    00000077
00000220    90300080
00000224    01010101
00000228    00000077
0000022c    90300084
00000230    00010301
00000234    00000077
00000238    90300088
0000023c    00000100
00000240    00000077
00000244    9030008c
00000248    00010000
0000024c    0000007a
00000250    90300090
00000254    0000000a
00000258    00000077
0000025c    903000b8
00000260    03000000
00000264    00000077
00000268    903000bc
0000026c    00000003
00000270    00000077
00000274    903000c0
00000278    00000200
0000027c    0000007a
00000280    903000c4
00000284    00000001
00000288    00000077
0000028c    903000c8
00000290    0f0f0000
00000294    00000077
00000298    903000cc
0000029c    0f0f0f0f
000002a0    00000077
000002a4    903000d0
000002a8    0f0f0f0f
000002ac    00000077
000002b0    903000d4
000002b4    0f0f0f0f
000002b8    00000077
000002bc    903000d8
000002c0    03000303
000002c4    00000077
000002c8    903000dc
000002cc    03030003
000002d0    00000077
000002d4    903000e0
000002d8    00030300
000002dc    00000077
000002e0    903000e4
000002e4    03000303
000002e8    00000077
000002ec    903000e8
000002f0    03030003
000002f4    00000077
000002f8    903000ec
000002fc    00030300
00000300    00000077
00000304    903000f0
00000308    03000303
0000030c    00000077
00000310    903000f4
00000314    03030003
00000318    00000077
0000031c    903000f8
00000320    010f0300
00000324    00000077
00000328    903000fc
0000032c    00010f00
00000330    00000077
00000334    90300100
00000338    0f00010f
0000033c    00000077
00000340    90300104
00000344    010f0001
00000348    00000077
0000034c    90300108
00000350    00010f00
00000354    00000077
00000358    9030010c
0000035c    0f00010f
00000360    00000077
00000364    90300110
00000368    010f0001
0000036c    00000077
00000370    90300114
00000374    00010f00
00000378    00000077
0000037c    90300118
00000380    0000010f
00000384    0000007a
00000388    9030011c
0000038c    00000001
00000390    00000077
00000394    90300120
00000398    00000700
0000039c    00000077
000003a0    90300124
000003a4    00187200
000003a8    00000077
000003ac    90300128
000003b0    02000200
000003b4    00000077
000003b8    9030012c
000003bc    02000200
000003c0    00000077
000003c4    90300130
000003c8    00001872
000003cc    00000077
000003d0    90300134
000003d4    00007a3a
000003d8    00000077
000003dc    90300138
000003e0    01020405
000003e4    00000077
000003e8    9030013c
000003ec    0f0f0103
000003f0    00000077
000003f4    90300140
000003f8    03030f0f
000003fc    00000077
00000400    90300144
00000404    00030300
00000408    00000077
0000040c    90300148
00000410    0f00010f
00000414    00000077
00000418    9030014c
0000041c    00000001
00000420    0000007a
00000424    90300150
00000428    00000010
0000042c    00000077
00000430    90300200
00000434    04120412
00000438    00000077
0000043c    90300204
00000440    04140414
00000444    00000077
00000448    90300208
0000044c    60010060
00000450    00000077
00000454    9030020c
00000458    00000044
0000045c    00000077
00000460    90300210
00000464    00750024
00000468    00000077
0000046c    90300214
00000470    40284028
00000474    0000007a
00000478    90300218
0000047c    0000000a
00000480    00000077
00000484    90300240
00000488    04120412
0000048c    00000077
00000490    90300244
00000494    04140414
00000498    00000077
0000049c    90300248
000004a0    60010060
000004a4    00000077
000004a8    9030024c
000004ac    00000044
000004b0    00000077
000004b4    90300250
000004b8    00750024
000004bc    00000077
000004c0    90300254
000004c4    40284028
000004c8    0000007a
000004cc    90300258
000004d0    0000000a
000004d4    00000077
000004d8    90300280
000004dc    04120412
000004e0    00000077
000004e4    90300284
000004e8    04140414
000004ec    00000077
000004f0    90300288
000004f4    60010060
000004f8    00000077
000004fc    9030028c
00000500    00000044
00000504    00000077
00000508    90300290
0000050c    00750024
00000510    00000077
00000514    90300294
00000518    40284028
0000051c    0000007a
00000520    90300298
00000524    0000000a
00000528    00000077
0000052c    903002c0
00000530    04120412
00000534    00000077
00000538    903002c4
0000053c    04140414
00000540    00000077
00000544    903002c8
00000548    60010060
0000054c    00000077
00000550    903002cc
00000554    00000044
00000558    00000077
0000055c    903002d0
00000560    00750024
00000564    00000077
00000568    903002d4
0000056c    40284028
00000570    0000007a
00000574    903002d8
00000578    0000000a
0000057c    00000077
00000580    90300300
00000584    00004005
00000588    0000007a
0000058c    90300304
00000590    00000001
00000594    00000077
00000598    90300308
0000059c    00020002
000005a0    00000077
000005a4    9030030c
000005a8    00020002
000005ac    00000077
000005b0    90300310
000005b4    00020002
000005b8    0000007a
000005bc    90300314
000005c0    00000003
000005c4    00000077
000005c8    90300000
000005cc    00000401
000005d0    00000070
000005d4    90300090
000005d8    00000008
000005dc    00000008
000005e0    00100000

# padding:
000005e4    ffffffff
000005e8    ffffffff
000005ec    ffffffff
000005f0    ffffffff
000005f4    ffffffff
000005f8    ffffffff
000005fc    ffffffff

#
# crc16/modbus of (settings+padding)
# (!) the size field at the beginnig is not included
#
00000600    00005de1

#
# empty space - erased bytes
# to the end of hws 4K block
#
00000604    ffffffff
*
00000ffc    ffffffff