Add anti theft CAN frame calculation

README.md

@@ -7,7 +7,7 @@ Wake up a Easylink (A-IVI) car multimedia system by CAN for using it on a table
 ## Attention
 
 - This will not remove or overcome anti theft protection
-  If the unit is locked and you have not access to the original ECUs or car it was installed into, it will not work. See below
+  If the unit is locked you need to login via DDT and copy the entered VIN and calculate a CAN frame to let it boot. See below
 
 - Please backup your NOR flash of the unit, if you want to use it with DDT often (you will! why boot a unit on your table), see details below.
 
@@ -216,10 +216,14 @@ Connect the clip again and erase, write and verify the contents.
 
 # Anti theft protection (system says locked)
 
-If you use a unit already installed in a car, anti theft protetion is enabled, which means the unit compare the entered VIN with the connected car. I found the can message which contains probably a part of the VIN so the unit will boot up. But I dont know how these message is calculated, because in the Easylink you just enter your VIN. (on locked units it is impossible to change or disable anti theft at least for now).
-
 If the unit is from a car which ECUs is partly working (Easylink is starting up in that car it will removed) you can read the CAN message which contains the VIN. You need to connect a CAN sniffer, dongle or something to the V-CAN, M-CAN or EXT-CAN and note the contents of the CAN ID 0x69F.
 
+If you can not capture the 0x69F frame from the donor car, you need to connect via DDT (it will work even it will says locked) and copy the entered VIN. Then calculate the neccessary CAN bytes with the last 7 digits from the VIN number backwards and add a F at the last byte. Here is an example:
+
+![Can frame calculation](doc/can_at_calc.png)
+
+Replace your number in the code and restart the Easylink system.
+
 # Debugging
 ## Serial console
 
@@ -245,4 +249,8 @@ I dumped the whole eMMC from a locked ebay unit with desoldering it. I wrote dow
 
 If you want to help you can spent me a coffee (Paypal: casc@pfalz-mail.de) or you can contribute yourself to this project.
 
-Feel free to optimize the code, reverse some CAN messages, reverse the VIN calculation, raise an issue or ask questions.
+Feel free to optimize the code, reverse some CAN messages, reverse the VIN calculation, raise an issue or ask questions.
+
+# Contributions
+
+[thomsoon](https://www.goingelectric.de/forum/memberlist.php?mode=viewprofile&u=93032&sid=5b05bc08106c54a9e03a373f066f2888) Anti theft CAN frame calculation