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Roku’s Ultimatum: Surrender Jury Trial Rights or Lose Access to Your TVs
(programming.dev)
This is a most excellent place for technology news and articles.
I had a .bin where the change hadn't been implemented and one after. Was using file carving tools as I was just trying to figure out what was going on. Probably spent too much time, but once I found out what it was doing, I was pretty mad. I tried to just corrupt the firmware to force a fallback to a "safe" state, but eventually I had to look into reverse engineering the binary that seemed to be controlling different things, such as the genuine ink check and things like that. Many hours of trial and error staring at the xxd and gdb output, semi randomly breaking things, until I seemed to break the right thing. Was bit tricky to get around the firmware signing, but eventually got that worked out too by tricking it into not checking (very old firmwares for that printer weren't signed) and accepting the 'new' firmware, with a much higher version number, as that's also one thing it checks to prevent downgrading.
Tools used as far as I remember were
binwalk
,foremost
,autopsy
radare2
Nice, ty. I've only revenged PC firmware, not embedded, so I wouldn't think of several of those tools.
I know a model of HP inkjet from my childhood that had a service/factory mode where ink checks were disabled. After years of claiming that its carts were empty I was suddenly able to print perfect full-colour pages. RIP HP Photosmart 3110