View source for Talk:John Deere Payload File

tl;dr: this wiki entry is somewhat bad. you cannot hack john deere tractor with a single empty file, dealerAuth.txt. it does not give dealer level access. it bypasses a screen saying "contact dealer." it does not apply to a tractor or any agricultural machinery.

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rant:

i think this page is somewhat misleading in regards to the dealerAuth.txt workaround. it cannot be used to "hack" tractors or associated farm equipment for root-level access; rather, it is solely used to bypass a "please contact your dealer to continue using this product" screen on the 4240 controller display (used to route a tractor and whatnot). [https://www.youtube.com/watch?v=z2_TLz9TpwY sick codes is responsible for disclosing this workaround] (bare youtube.com link; the timestamp is ~around 24 minutes), and i wish to summarize their work now (since i find it really neat)! the display was rebooted 10 times without fully starting. there is a simple plain text file that holds a count of failed reboots, and upon reaching 10 the display will refuse to boot and instead will display a message saying "this is broken, please contact the dealer to fix." the way a dealer can bypass that (that is not reported anywhere to an end-user), aside from them {de,re}soldering the nand flash and modifying that text file, is to put the empty file dealerAuth.txt onto the root of a pendrive which will allow the display to boot, subsequently resetting the counter (or maybe it resets it first? either way the end result is the same). keep in mind this is only for that one screen when the display fails to boot 10 times over -- sick codes got root access by simply spawning xterm in a cron job on the running x.org server (crontab -e'd through modifying the nand flash directly) every 2 minutes. payload files are [https://publicinterestnetwork.org/wp-content/uploads/2023/07/Service-Obstructor-Full-Report-1.pdf still not uploadable by an end user] (page 18, credible enough of a source i reckon), and one must go to the dealer directly! by the way, the news article cited barely makes the distinction of "root level access vs. bypassing one screen on boot," and this here wiki entry mischaracterizes it further. i see how this mistake could have happened and it tripped me up, too~