Nikon Firmware Insights #03

The B firmware is were the major action is, and it’s based on the Fujitsu FR chipset. This seems to be the same chip as used by the earlier Nikon DSLRs and the Pentax cameras.

Looking at the B firmware you can see text, for example English @ 0x5ACC68 to but the table of addresses prior to this text block have the same relative spacing of values but are 0x40000 bytes higher in value.

Browsing elsewhere in the file, shows this pattern holds up for the entire file. You can check by finding some text, ad 0x40000 to the text file address, then search for that resulting hex value, ta-da

So we can assume the code is loaded starting at 0x40000.

Next is what we are going to decode the file with. If you have commercial version of IDA Pro then your in luck as it comes with the Fujitsu FR CPU decoder built in. I only have the free version, so am not so luckly.

Kevin Schoedel however has written a pretty good dissembler for the FR CPU, as part of previous Pentax firmware work. I struggled to get the original code working correctly, so I rewrote it in C# and now understand how to use it, and really appreciate his efforts. But I am left oh-so-much wanting IDA Pro style everything. The worst thing is I almost want to pay the $500USD to have that IDA Pro magic, but if I have that money ‘spare’ why didn’t I just buy the D7000 to start with.

Anyway, my present D5100 B firmware DFR import file looks like:

# File map: D5100
-i 0x00040000-0x00BFFFFF=0x00000000

# Memory map:
-m 0x00040000-0x00040947=CODE
-m 0x00040948-0x000409b3=DATA:L
-m 0x000409b4-0x00050068=CODE

# interupt vector table.
-m 0x000dfc00-0x000dffff=DATA:L

#-m 0x000e0000-0x0x000fffff=DATA:L // this is 0xFF rubbish

-m 0x00100000-0x00236A4A=CODE

and heres my C# port of DFR, to use the above with.

If Ilfak wants to give me a free copy of IDA Pro, or even just the FR processor that works with 5.0, I would be very humbled.

The FR – CM71-00101-5E.pdf instruction manual from Fujitsu is very useful.

Here the first 0x4a bytes of the firmware, you can see the interupt vector table being loaded at 0x4002c.

Disassemble 0x00040000-0x00040947 (file 0x00000000) as CODE

00040000 (00000000)  9F80 5000 0000         LDI:32  #0x50000000,R0
00040006 (00000006)  C011                   LDI:8   #0x01,R1
00040008 (00000008)  1501                   STH     R1,@R0          ; 0x50000000
0004000A (0000000A)  9B00 03E0              LDI:20  #0x003E0,R0
0004000E (0000000E)  9F81 4700 0000         LDI:32  #0x47000000,R1
00040014 (00000014)  1401                   ST      R1,@R0          ; 0x000003E0
00040016 (00000016)  9B00 03E7              LDI:20  #0x003E7,R0
0004001A (0000001A)  C031                   LDI:8   #0x03,R1
0004001C (0000001C)  1601                   STB     R1,@R0          ; 0x000003E7
0004001E (0000001E)  8710                   STILM   #0x10
00040020 (00000020)  9F8F 6800 0800         LDI:32  #0x68000800,R15
00040026 (00000026)  9F80 000D FC00         LDI:32  #0x000DFC00,R0
0004002C (0000002C)  B300                   MOV     R0,TBR
0004002E (0000002E)  9B00 0600              LDI:20  #0x00600,R0
00040032 (00000032)  9B41 0185              LDI:20  #0x40185,R1
00040036 (00000036)  1401                   ST      R1,@R0          ; 0x00000600
00040038 (00000038)  9B00 0640              LDI:20  #0x00640,R0
0004003C (0000003C)  C401                   LDI:8   #0x40,R1
0004003E (0000003E)  1401                   ST      R1,@R0          ; 0x00000640
00040040 (00000040)  9B00 0680              LDI:20  #0x00680,R0
00040044 (00000044)  9F81 799F 9910         LDI:32  #0x799F9910,R1
0004004A (0000004A)  1401                   ST      R1,@R0          ; 0x00000680

The second address in parens is the original file offset to help with looking up the file.

 

Interested in more, come join the us at Nikon Hacker, or use the Online Patch Tool (Help)

10 thoughts on “Nikon Firmware Insights #03”

  1. Awesome! You guys are the best! I think if you setup a paypal account, there will be probably a lot of people out here, who would be willing to donate 5-10$ each to get you the software tools you need so that there might be some day a “Magic Lantern” firmware for the D5100/D7000 :)

  2. Thanks for the complement. Not sure on the pay pal front. At one level your correct it would help to get the $$ to buy IDA Pro, and on the other front would then make feel I owed people some results. Whereas at this point I’m scratching my own itch.

  3. Can you hack the Nikon CX-cameras with these tools?

    Nikon CX-cameras would be great if the video features could be improved to include 24/25 fps 1080p with decent bitrates and intraframe codec. I’m sure that the expeed 3 processor is capable of 120 fps 720p at modest bitrates. Not too sure about the internal buffers though.

    The CX-format could be the super 16mm digital with those improvements; sensor size is nearly identical to super 16 frame. There are some very, very nice cinematic lenses available for that format…

  4. Hi,
    realy great work,
    please do not abandon this project,
    as “nikonsteve” says if you need please create a paypal account,
    I’m sure you will do everything possible, with or without result, I believe in your passion.

    Thank you.

    P.S. sorry for my english

  5. Sorry but i don’t understand a lot

    I just want to ask very simple question, is there a way to replace the D5100 firmware with D7000 , or even add features like full manual video exposure control to D5100 !!

    Thanks for your effort & Time

  6. Currently there is not a way to replace anything. What this effort allows is for the firmware to be disassembled, thus understood.

    Before altered firmware can be loaded onto the camera, the checking code needs to be understood, so alter firmware can be marked as ‘good’.

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