Browsing all articles from March, 2011

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Kudelski N3 bits and pieces, plus thoughts on key / rsa extraction from flash.
N3 Notes mostly from forum posts by TheCoder

These are notes for future reference more than anything else, so please no excited emails about how its wrong, or right, or can I hack your box.

There are three different pairing methods used N3 boxes presently. These are DT06, DT08 and Secondary key.

The DT06 method transfers a compressed form of an rsa pq keyset from which the CAM public/private rsa keyset and its associated modulus can be derived.

The DT08 method transfers the cam modulus along with the IRD number of the married box. The public rsa key is not transferred but it is implied that the box already knows this value.

The Secondary key method does not involve a transfer. It imples that the box already knows the cards matching CAM modulus and rsa public key value.

Various boxes, depending on make/model, may use any of the above pre-pair key transfer methods but it could be useful to know which box uses which method.

1 Stick your N2/N3 card in your card reader
3 Select the Comm Tab. This should give you an upper and lower text pane
4 Cut/Paste the scriptt below into the top pane
5 Press the “Send D2C” button/icon
6 Results should appear in bottom pane
7 Interpret your results based on info below.
Script – Read DT06/DT08

tx 21 C1 01 FE 1F
tx 21 00 08 A0 CA 00 00 02 12 00 06 55
dl 02 00
dl 02 00
tx 21 00 09 A0 CA 00 00 03 22 01 00 1C 7E
dl 02 00
dl 02 00
mg *
mg *** DT06 info ***
tx 21 00 09 A0 CA 00 00 03 22 01 06 13 **
dl 02 00
mg DT06 response1
dl 02 00
tx 21 40 09 A0 CA 00 00 03 22 01 86 13 **
dl 02 00
dl 02 00
mg DT06 response2
mg *** End DT06 info ***
mg *
mg *** DT08 info ***
tx 21 40 09 A0 CA 00 00 03 22 01 08 13 **
dl 02 00
mg DT08 response1
dl 02 00
tx 21 00 09 A0 CA 00 00 03 22 01 C8 55 **
dl 02 00
dl 02 00
mg DT08 response2
tx 21 40 09 A0 CA 00 00 03 22 01 88 55 **
dl 02 00
mg DT08 response3
dl 02 00
mg *** End DT08 info ***
Just to clarify :
The important bits your looking at are the DT06/DT08 responses (the bits that start with Rx: )
ie RX: 12 00 15 A2 11 08 E0 00 00 00 5E 01 20 00 00 00
00 00 00 00 00 00 90 00 B3
RX: 12 40 15 A2 11 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 90 00 64
RX: 12 00 15 A2 11 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 90 00 24
RX: 12 40 57 A2 53 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 90 00 64

If the responses vary significantly from the above, with the 00’s replaced with some varying data, then its likely your card had the specified tier and is probably using the corresponding pairing method.

If the DT06 response contains lots of 00’s then its NOT DT06 pairing
If the DT08 response contains lots of 00’s then its NOT DT08 pairing
If its not DT06 or DT08 then its probably secondary key.

For non DT08 cards (mostly the newer boxes) each box has a unique cam_n already built into its firmware – this can only be extracted from the actual box itself.

About the Algorithm,

N2 encrytion was based on the following algorithm ->
decrypted message = ( (IDEA( ( (EncryptedMsg ^ 3)Mod N1) ,IdeaKey) ) ^3) Mod N1
Thats 2 distinct algorithms. An RSA algorithm (performed twice) and an IDEA algorithm.
The key for the RSA algorithm is something like –
RSA EMM-G=15A811B2065DF39CD48C9C958E7B406345295B09D0E9A18A 9B92C5FD7761CAAFAB830880F1F06B4E4477F157EA10D0AFC3 FDDB1ED2E7E83E89F03FF81237047DB76F79D6A2CFD75A7255 D72E52E7F47B96C2DFBDEBFC80CE927F6AD351FDF0BF8DA13F F62295BFBAF29035A230136D0B4AA99D38DD8B0465F2C709FC 8818173C
Which, as you can see, is a 128 byte (1024 bit) number. This is the main encryption key for EMM decryption.
The IDEA algorithm, which acts as an inner layer to the RSA has a standard 16 byte (128 bit) IDEA key.
There is no algorithm in N2 (or N3) that only uses an 8 byte (64 bit) key although some providers have opted to use 3DES rather than IDEA as an inner layer. This uses three separate 8 bye (64 bit – only 56 bits used) keys to form an amalgam 168 bit DES algorithm.

If Using DT08 (0a) on the card :
The Dt08 (0a datatype on card) is created by the provider and sent to the card at sub time.
The dt08 contains the Cam N public rsa key along with ird/boxkey.
The dt08 is IDEA encrypted with the Idea Key made from ird/boxkey/inverted ird.
The dt08 is RSA encrypted using Ird N (public rsa key) and Ird D (private key and uknown by anyone but provider).
Ird N = N1 xored N2
Ird N1= A4E9B585932F90282FD70C908176E8605E6B2CE629335A0FC1 5B31DAB0BFC6FEEB88CFC69649994CD3FE039C9965C620C4D5 828E9153998EE4AE0E8C25644DF3 xor
Ird N1= 237280AAB36BE4B21FC71FBF08218E532A545E744D7B007FF8 69BA426831C4AC653F3825ADE9358FCD1F0239EC447CBC2765 CC0AEBE437AF2270FC461C2FA042
Ird N = 879B352F2044749A3010132F89576633743F729264485A7039 328B98D88E02528EB7F7E33BA0ACC31EE101A57521BA9CE3B0 4E847AB7AE21C6DEF2CA394BEDB1
The Ird N1,N2,Ideakey exist in the tsop.
Ird E = 3
Ird D = UKNOWN, this is the reason you can’t create your own dt08 without changing the N1/N2 on the tsop, you must know Ird D.

DT08 (0A) = IdeaEncrypt(CamN/Ird#/Boxkey/Idea Signature,Ird_Ideakey) ^ D mod Ird N.

Ird requests DT08.
Card sends back the dt08 (0a)
Ird decrypts the dt08.
Decrypted dt08 = IdeaDecrypt(DT08,Ird_IdeaKey) ^ 3 mod Ird N.
It checks the ird # and boxkeys in the Decrypted 08 if they match what is on ird,
it stores the Cam N in the decrypted 08 in ird memmory.

If Using Secondary Key (SK) on the Ird.
Ird checks for SK exists on the ird, if it does, the dt08 will never be requested/ignored from the card.
Ird validates the SK with idea signature in the SK (using IIIIIIII01924314051647990A9C4E1 where I = irdnumber).
Ird takes the Cam N in the SK and puts it in ird memmory
Note : Cam N is not even encrypted in the sk, very weak method compared to dt08.

Later, establish session key (0C datatype on the card):
Ird requests 2a data from card.
Random 2a is sent from card to ird.
Ird performs some Idea signing (leave it to you to look up 2a/2b routines)
Ird comes up with session key from the 2a message sent from Cam.
Ird encrypts the session key with rsa.
Encrypted 2B = (2B data with 16 byte session idea key) ^ 3 mod Cam N.
Sends encrypted data back to card in 2b message.
Cam decrypts 2B with Cam N, Cam D. Decrypted 2B = (Encrypted 2B) ^ Cam D mod Cam N.
If valid, store session key in ram and on card for later use.

This all happens as ird boots.
When you select a channel.
Ird sends Cmd 07 ECM message with control words encrypted.
Cam decrypts the control words rencrypts them with Idea encryption using the session key established above.
The ird then requests the control words.
The Cam sends them back in the 1C response.
The ird decrypts the control words with with Idea encryption using the session key established above.
Sends the control words to the mpeg decoder.
8 seconds of video.
Repeat 07/1C process over and over.


and pay special attention on CMD$2A ??

it should reply the CAMID serial number + 64 bytes random key generated and then shortly after encrypted with the CAM(AKA Conditional Access Module or SmartCard) RSA primary 96 bytes from the card… the so famous RSA modulus keys 96bytes at eeprom $8xxx on the ROM110 days.. From the card (this cmd is also the first step of the SessionKey negotiation)

shortly after the receiver receives this card reply.. and will decrypt it using the Secondary Key which is also 96bytes, this key is build up by using the following information stored in the receivers flash..


total 96 bytes..

IR = Receiver serial number
XX = Unimportant
EE = RSA public exponent for STB
F1 = SK signature 1 used to calculate the box key
F2 = SK signature 2 used to calculate the box key
SK = RSA public modulus N
CR = CRC Checksum
BB = BoxKey result from xoring F1 with F2 keys stored in the flash firmware from the receiver

once we decrypt the cmd2A we extract from inside the original 64byte random key generated in the card, then we will apply the IDEA encryption algo on the first 32bytes from the 64 byte random key to hash out the session key.

So this first 32 bytes are extracted from the 64byte random key and will be encryted using the IDEA SIGNATURE key… this key will be generated by the following information

IdeaKey generation

BBBBBBBBBBBBBBBB = Boxkey result from F1 xor F2
CCCCCCCC = IRD number from receiver stored in Flash firmware
CA MI DC AM = CAM ID or Smart Card serial number converted in HEX, which can also be extracted by simply sending INS CMD$12 to the card..

so the IDEA signature key for encrypting the first 32bytes extracted from the 64 random seek key is


once applied the IDEA encryption we will have the result 16 byte sessionkey.. which will be stored in the receiver flash for a few hours… to be more precise around 5 hours..

Now going back to the calculation done before, the receiver decrypted the cmd$2Aencrypted by the card with the RSA primary 96 stored in the card.
once decrypted it simply just extracted the first 32bytes of the 64 byte seed key generated by the card. this 32 bytes were used for calculation of the 16byte sessionkey..

but, before the 32byte keys was taken for the idea signature encryption.. the receiver.. re-encrypted the 64byte random key using the SECONDARY KEY RSA 96 stored in the receiver flash, which i just stated above how to get this key…
and will send it back to the card on cmd$2B

the card will receive the cmd$2b and will decrypt it using the PRIMARY RSA modulus key 96.
and will extract just the first 32bytes.. and by using the BOXKEY+IRD+CAMID stored in the card, the card will also calculate the same 16 byte session key.

in orde to make the card pairing , u need to know the RSA_N+BOXKEY+IRD NUMBER+CARD SERIAL number or CAMID…

then with them all together we can start comunication between the card.. and on the CMD$2A and $2B we will have the SessionKey negotiation which i just explained previously.

if for example on one side or the other we have different BKand RSA… we will a session key failure.. and without this Sessionkey we will not be able to decrypt the CM$1C or $9C related stuff

this means that if negotiation of session key succeds, then the receiver will send the ECM$07 to the card, which will then be decrypted by simply just using the ECM RSA modulus key and the ECM IdeaKey to decrypt the Control Words / CWs.

once they are decrypted the card will send them to the RECEIVER.. this is normally done via CMD$1C obviously this CMD is encrypted with the Sessionkey 16 BYTES described above.. once it arrives at the Receiver end, you will use the same Sessionkey 16byte to decrypt that CMD$1C and extract the REAL DCWs Decrypted Control Words to open up the Video and Audio stream related for that XX amount of seconds…

Now this Session key is refreshed every 5 hours.. this means that every 5 hours a new session key is produced.. so every 5 hours the card generates another 64byte random seed key using other RSA algo inside the card.., and will then send this 64 byte seed key to the receiver again.

Shortly followed by all the procedure described above to extract the new session key again.


Given that ==================================================
11111111<----------------------------FIRST 4 BYTES---- IRD XXXXXXXXXXXXXXXXXXXX<--NEXT 10 BYTES---- unknown 1111111111111111<--------8 BYTES---- Y1---WRITE DOWN ================================================== 11111111111111111111111111111111-_ 11111111111111111111111111111111-_-_"N" 64 Bytes 11111111111111111111111111111111-_- 11111111111111111111111111111111- ================================================== 1111111111111111<-------8 BYTES--- Y2-----WRITE DOWN XXXX<-------------------2 BYTES--- CHECKSUM ================================================== Y2 Xor Y1 = BOXKEY ================================================== 006e convert from hex gives you 110 bytes block cipher ird 4 bytes bk 8 bytes sk 96 bytes leaving us with 02bytes used to encrypt, decrypt above. eg: 00 00 00 6e 34 0d 20 1c 03 03 70 80 5a 8e dd 24 ac cc a4 a6 e2 da 86 91 29 18 0b a6 23 6d fa c4 05 7f 1b 20 97 eb 0c 19 b3 39 2f 1e cb 9b 67 4d ed 10 f5 65 ec 0d c7 35 ac f0 b8 89 b0 51 59 22 69 85 d5 f1 93 48 7a 84 6e 1f b4 24 83 79 db 02 4d b0 9c 5e 8b df 89 57 9c 5a 7f 9a cc 87 51 3b 15 6b 15 cc c4 2f 66 e7 e6 75 4f 24 f2 07 85 0d db b0 3d e2 64 dd e9 54 ad 77 60 e7 8f a6 cd a6 46 c3 b8 fa e4 e7 51 2d 6a 2f 95 68 56 b5 78 34 17 6b b8 48 38 87 c4 95 e5 b0 41 2c 95 e1 24 aa 4b 2a 6f 8c 90 53 29 a9 6b 3d 0a b5 92 1c 95 ec 72 b9 54 a9 99 f5 f3 dd f4 0f 60 c3 25 5b 5b 81 22 e8 79 c5 be 8f 3c 89 2b 8a ad ba 27 b0 c2 f7 b1 4f 08 d5 37 2a 97 c5 f0 07 9d 99 be c7 8a a9 cf 5a c5 45 ce 1e 25 43 81 95 7a 22 33 ed 93 74 Gives: 00 00 00 63 (length) 0d 20 1c 03 03 70 80 5a 8e dd (unknown) 24 ac cc a4 a6 e2 da 86 (y1) 91 29 18 0b a6 23 6d fa c4 05 7f 1b 20 97 eb 0c 19 b3 39 2f 1e cb 9b 67 4d ed 10 f5 65 ec 0d c7 35 ac f0 b8 89 b0 51 59 22 69 85 d5 f1 93 48 7a 84 6e 1f b4 24 83 79 db 02 4d b0 9c 5e 8b df 89 (64 bytes) 57 9c 5a 7f 9a cc 87 51 (y2) Y2 XOR Y1 = 0x579c5a7f9acc8751 xor 0x24accca4a6e2da86 = 42 12 8C F2 39 39 55 FA So, a flash dump would be helpful.. Possible Scenario's - BGA, TSOP, TLGA etc.. desoldering for Flash. Put in a socket. eg from or

Pop flash back onto something else, read, dump. eg

Get box key, rsa key (if req. based on a check of DT type from the actual subbed card)
Pop flash back in socket.

Been there, done that for data recovery on faulty flash drives, plus most of the places I know down at QJlu have SMD / BGA desoldering capability or better.

Bunnies blog is fairly good at explaining the basics (albeit for xbox) –

Most boxes use ARM based SoC’s for things. Also possible to just throw up a dev board, and interface to that.

Although most boxes also have some form of OS running, so just as feasible to dump flash that way also assuming serial or jtag access and a bootloader is available.

Amusing that people like claim this is hard – there are plenty of tools for this already out there eg softcenter, pc3000, plus all the local chinese stuff. Semi ok forum here talking about flash recovery, although not as technical as I’d like.

Once key(s) are had, then I can use my own decoder rather than the crappy one the broadcaster uses.


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Had a client come into the office today with a locked iPhone.

Normally this isn’t really a big deal (assuming that there is a hack for it), but in this case, it was a little more complex, as he didn’t have working wifi.

PwnageTool has a great feature where you can add Cydia Packages to a custom firmware, so that you can prepackage the firmware already to go.

So, I opened up PwnageTool, added the site to the Cydia sources section in advanced, and tried to load in Ultrasn0w.

Life isn’t easy, and it didn’t work.

But why didn’t it work?

I took a look at a working site, and checked out the differences between their package section and Ultrasn0w’s.

Ultrasn0w is hosted on
While their website doesn’t really tell you much useful information, a bit of googling lead to some info.

The .deb file (debian package file) on their site is at

Cydia usually needs stuff in a particular format, so I next checked out how one makes a repository.
This is documented at Saurik’s site here –

Basically, you throw files into a folder and make a Packages file.

The example given on Saurik’s site is this:

/web/apt/xmpl]# dpkg-scanpackages -m . /dev/null >Packages
** Packages in archive but missing from override file: **

Wrote 1 entries to output Packages file.
[root@desktop:/web/apt/xmpl]# bzip2 Packages
[root@desktop:/web/apt/xmpl]# ls -la *
-rw-r--r-- 1 root root 906 2008-07-01 07:48 MyProgram.deb
-rw-r--r-- 1 root root 380 2008-07-01 08:00 Packages.bz2

So, it appears we need a Packages.bz2 file.

Being adventurous, I decided to setup my own repo, and stuck the .deb file for Ultrasn0w in there.
Followed the instructions and created the Packages.bz2 file.

Tried again in PwnageTool, and… No go.


Does have a Packages.bz2 file?
Why yes it does.

Take another look at the working one – ahah says my brain.

They point the folder to the _uncompressed_ Packages file.
I guess PwnageTool doesn’t support compressed Package list files.

So, I try that out using an uncompressed file.
Created the Packages file with

dpkg-scanpackages -m . /dev/null >Packages

and try again.

Better – I’m getting a result now with my repo when I click refresh.
However, I can’t seem to be able to download any files…

So, lets take a look at whats happening in my apache logs. - - [07/Mar/2011:20:50:52 +0800] "GET /dists/Packages HTTP/1.1" 200 1643 "-" "PwnageTool/4.2 CFNetwork/454.11.5 Darwin/10.6.0 (i386) (iMac9%2C1)" - - [07/Mar/2011:20:51:06 +0800] "GET /./mobilesubstrate_0.9.3228-1_iphoneos-arm.deb HTTP/1.1" 404 1184 "-" "PwnageTool/4.2 CFNetwork/454.11.5 Darwin/10.6.0 (i386) (iMac9%2C1)" - - [07/Mar/2011:20:51:42 +0800] "GET /./ultrasn0w.deb HTTP/1.1" 404 1164 "-" "PwnageTool/4.2 CFNetwork/454.11.5 Darwin/10.6.0 (i386) (iMac9%2C1)"

Aha! While its successfully found the repo now, its looking for the files in the wrong folder – my repo is in /dists, and its looking in the root folder.

Seems the Saurik instructions are a bit mangled, or the Package generator is a bit silly.
Quick look at the helpfile shows it needs the folder via -m

So I went up a level, and regenerated my file.

cd ..
dpkg-scanpackages -m dists > dists/Packages

Yes, it works!

Now PwnageTool can download my file finally. Yay!

I just need to select it in PwnageTool / Packages as below, and build my ipsw to test.

Now I can finally make my own Ultrasn0w firmware woohoo!
Not as hard as it seems, but not as easy either!

I’ll leave my UltraSn0w repo at for now, but will probably move it elsewhere at some point, and update this post. So, if you need it, get it while you can.


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This was posted by myself over at BimmerForum’s, but as China’s Firewall is being particularly unpleasant these days about what sites I can and cannot visit, I thought I’d repost it here, so its more accessible for me.

Note – I no longer own a 7 series, so any requests for modded rom’s should probably be accompanied with nice gifts to persuade me to do the work involved 🙂

As I saw people asking about Tuned ROM’s in another post I thought I’d do some research.

Its quite niche – hence the ridiculous pricing people charge for roms – time is money though!

Here’s my research so far. I’m basing it on the E32 735iL 1989/1990, as thats what I own (and can test for).

Googling for E32 735iL gives:


BOSCH 0261200179
BMW 1730697

Vehicle Applicability:
BMW 3′ E30 320i Touring 2.0 95kW/129PS (M20/ 206EE/KA)
BMW 5′ E34 535i 3.4 155kW/211PS (M30/346KB)

BMW 6′ E24 635CSi 3.4 155kW/211PS (M30 B35)
BMW 7′ E32 735i 3.4 155kW/211PS (M30/ 346KB/EC)
BMW 7′ E32 735iL 3.4 155kW/211PS (M30/ 346KB/EC)


BOSCH 0261200179
BMW 1722611

Vehicle Applicability:
BMW 3′ E30 320i Touring 2.0 95kW/129PS (M20/ 206EE/KA)
BMW 5′ E34 535i 3.4 155kW/211PS (M30/346KB)
BMW 6′ E24 635CSi 3.4 155kW/211PS (M30 B35)
BMW 7′ E32 735i 3.4 155kW/211PS (M30/ 346KB/EC)
BMW 7′ E32 735iL 3.4 155kW/211PS (M30/ 346KB/EC)

ETK however says

No.Description Supplement Qty Part Number Price
01AT-Control unit Motronic HARDWARE 1.3 1 12141738168 ENDED
01AT-Control unit Motronic HARDWARE 1.3 1 12141748258 $813.86

Whatever the actual revision used, its pretty clear we have a v1.3 Motronic.

Wiki (

Motronic Motronic

) says:

The Motronic 1.1 System was used by BMW from 1987. This was then superseded in 1988 by the Motronic 1.3 system[6] that was also used by PSA on some XU9J-series engines (which previously used Motronic 4.1).[5]
The Motronic 1.1 and 1.3 systems are largely similar, the main improvement being the increased diagnostic capabilities of Motronic 1.3. The 1.3 ECU can store many more detailed fault codes than 1.1, and has a permanent 12-volt feed from the vehicle’s battery which allows it to log intermittent faults in memory across several trips. Motronic 1.1 can only advise of a few currently-occurring faults.[6]
The systems include a knock sensor for ignition timing adjustment and the option for a lambda sensor, enabling their use with catalytic converter-equipped vehicles.[5]
The ECUs have 2 injection outputs, and the injectors are arranged in 2 "banks" which fire once every two engine revolutions. In an example 4-cylinder engine, one output controls the injectors for cylinders 1 and 3, and the other controls 2 and 4. The system uses a "cylinder ID" sensor mounted to the cam-shaft to detect which cylinders are approaching the top of their stroke, therefore which injector bank should be fired. During start-up (below 600 RPM), or if there is no signal from the cylinder ID sensor, all injectors are fired simultaneously once per engine revolution.[6]

DME / ECU 1.3 Info.

Tuning is set in 2D map.

Motronic 1.3 from 1989: The fault code memory is extended to contain all fault codes that are detected by the EMS.
In vehicles sold in the USA, when the ECU detects that a some faults are present it earths pin 15 and the Check Engine warning lamp on the dash will light. The lamp will stay lit until the fault is no longer present. A warning lamp is not fitted to vehicles sold in other markets. The faults that will turn on the lamp are mainly those concerned with emissions. Other faults are logged by the ECU but the lamp will remain out.

ECU (DME) sensors run off 5v

Download extended info here –

DME bootup: (roughly paraphrased)
Interestingly enough I got to learn this properly via the tips and tricks for checking why the car doesn’t start..

Ignition switched on:
ECU earths 85 , 36 which causes relay to close and 30 is connected to 87 starting the fuel pump. (30+87 can be bridged manually under the green relay to test pump). Its opened for +- 1 second.

Next up it reads values from the CAS (Pulse Sensor). If it reads a speed signal (aka is it turning), so fuel pump stays on.

CAS is used to time the pulses (read from each turn of the flywheel), this is checked against the map file for correct speeds (need to use a multiplier for the map values vs the flywheel pins).

The Motronic ECU contains a fuel map with an injector opening time for basic conditions of speed and load. Information is then gathered from engine sensors such as the AFS, CAS, CTS, and TS. As a result of this information, the ECU will look-up the correct injector pulse duration right across the engine rpm, load and temperature range.

The injectors are arranged in two banks with injectors 1 and 3 (4 cylinder) or 1, 3 and 5 (6 cylinder comprising one bank, and injectors 2 and 4 (4 cylinder) or 2, 4 and 6 (6 cylinder) making up the other bank. Each bank is connected to the ECU via an independent ECU pin.

The Motronic 1.1 & 1.3 multi-point injection system pulses the injectors semi-sequentially and once every two engine revolutions. During engine start-up below 600 rpm the ECU pulses all injectors simultaneously. Once 600 rpm has been attained and if the ECU has received a signal from the CID sensor, each injector bank will be pulsed alternatively according to which pair of cylinders are approaching TDC. If a signal is not received from the CID sensor the injectors will remain on simultaneous operation. However, if the CID sensor subsequently sends a signal to the ECU after the engine has commenced running, the ECU will pulse the injectors semi-sequentially after the next deceleration phase – even if the CID sensor then ceases to send a signal.

Motronic troubleshooting (aka code readout)

The fault codes for these systems will appear on the check engine light when you turn the ignition key to the On position (but dont start it), then: fully depress the accelerator pedal, then fully release it. Repeat the depress,release cycle 5 times fairly quickly, but not too fast. It should be completed in a few seconds. What you are doing here is clicking the wide open throttle switch then the idle switch each 5 times. This signals the Motronic unit to send the fault codes by flashing the Check Engine light. You should see the light flash once then it will start flashing the 4 digit codes. If there are no faults, you should see the 1444 code (and 2444 if you have a 12 cylinder). The codes appear as a series of flashes for each digit. The flashes indicating one digit are about 1 second apart, the next digit appears after a couple second interval.

Get the codes from:

Other notes:

CPU most likely 8051
EEPROM 26C256, so 32KB / (32768 byte) chip. 28 pin.
Can also use a 64KB chip, just ground the relevant pins for which 32kb to use or burn one rom at appropriate location. Useful for running 2 tunes – eg original and second.

Tools available for this eg….html?cPath=31

Should run from a AT29C256 or similar.

ECU interesting pinouts:

Pin 55 TX
Pin 13 RX
Pin 2/19/24/26/14 GND

File layout (unchecked)

AFR idle: 0x662E (pos 26158)
AFR partial: 0x6662

AFR full: 0x6640

ign idle: 679A
ign partial: 0x67FE
ign full: 0x67CC

Sample bin file here:…y-Motronic.bin

(I’m having issues downloading that from China, so haven’t checked it yet against the alleged layout).

Table calculations:

fuel maps correspond to (value/128 +1)*lambda_1

Bosch-Motronic f(n) = (n-30) x 0.75
some Bosch f(n) = (n-509) x 0.75

Bosch KE-Motronic und Mono-Motronic
f(n) = [(255-n)/6] +1

Motronic info

Very useful info for looking this up from

Maps 20 bytes each

Other thoughts – now we know what pinouts / values are expected in the system, guess just need to see what equipment provides appropriate inputs. eg, replace expensive spares with cheaper/better modern versions.

Most of the differences are usually in the mounting afaik, not the tech.

Motronic pinouts and board details here –

Lots of people working on this kind of thing with software like tunerpro / xdf (map) files.

*Good* forum for info (although not relevant to the Bosch ECU’s, but concepts / strategies same)…uide-book.html

The motronic 1.3 software in most of the E32’s should be fairly easy to modify – its all been documented well online before, so just a matter of getting a few rom files for specific models, and comparing tables.

Shogun has at least one rom (as he’s burning and selling them according to another post).
I can extract the current one from my DME and make a bin file for comparison.
We also have the rom from…y-Motronic.bin

Should be enough to see where the changes are for the E32 / 8051CPU Motronic 1.3 anyway, so that I can tweak.

Another lucky thing is that I also used to write embedded software on 8051 cpu years ago (although I’ve forgotten it all by now)

Any interest in this from others (I’ll need more rom’s though)?