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pb4ugoout / Jamboard

Repo detailing the hardware breakdown down of a Google Jamboard in an attempt to assist in getting a build of Lineage OS created for it.
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instructions about how to run L4T on the Jamboard carrier board #1

Open bbf opened 2 weeks ago

bbf commented 2 weeks ago

Hello,

I saw your post on the Android forums that you managed to run L4T on the Jamboard, and saw the specific version you used on one of the markdowns here. Thank you for sharing that. Would you be willing to document the steps you took to flash L4T into the Jamboard?

Thanks

pb4ugoout commented 2 weeks ago

I can do my best. I sort of abandoned the project. I don’t know enough coding or enough about Android to make my own build of LineageOS for the Jamboard hardware.

It’s a fairly straightforward process but you will need a spare Jetson TX1 or TX2 module as the one inside the Jamboard is fused and without keys from Google there’s no way to load any other software on to it.

You can follow along with my photos and tear down to remove the back panel. That’s the hardest part of the whole thing. The rear panel is actually beauty panel. Pop that off first. Then unscrew the actual back cover. The clips are tough and the plastic is huge. Be prepared for LOTS of screws as well. Once inside you can remove the 4 screws from the heat sink/passive cooler and then the 3 screw securing the module to the carrier. Just replace the module with your own and flash L4T using the rear usb port on the Jamboard. It’s the micro by the power plug in the middle of the back. One of the volume buttons is the recover button. Hold that down and press and release power. That will put your module into APX mode so that you can flash L4T.

If my documentation is unclear please let me know. I never meant to give the assumption that you could flash the factory module without opening up the unit.

Is that helpful?

bbf commented 2 weeks ago

I actually opened up my Jamboard yesterday, and took several pictures of the internals, before giving up on the hardware hack approach, and trying again to take a software based approach. I'm a software engineer, and even have worked for Google, but I don't have any insider info on the Jamboard. I decided the software approach because I thought that by doing a "fastboot oem unlock" (which did work, its not locked) I could perhaps provide a L4T kernel and trampoline out of the Android (perhaps Things) shell they built. I'm by no means an expert on Android, specially their boot process, but I have done my fair share of flashing custom roms and building lean distros for embedded hardware a long time in the past.

Thank you for the info on how you achieved L4T with a different Jetson module. I would be happy enough if I could get Linux running on the Jamboard if I can get most of the hardware working. Even their camera module seems to be custom (Chicony maybe custom built it for them), and there's some issues when used as a standard UVC device.

If you are interested in collaborating, I'm willing to help on the software side on what I can. I noticed someone else trying something similar: https://gitlab.incom.co/CM-Shield/android_device_nvidia_foster/-/commit/49814dbbf198e91863a88c301ca589dc3140fa97#

I can politely ask some ex-coworkers at Google for some information (especially after the October date), although I think the original team has already been disbanded, so bit rot will take over soon.

bbf commented 2 weeks ago

I think @webgeek1234 is the owner of the gitlab above, and he pushed that change a couple of days ago. It seems he actively participates in many parts of LineageOS. Perhaps there's some hope on making this work... I'm going to setup a local build env for LineageOS and see how far I can get.

webgeek1234 commented 2 weeks ago

I think @webgeek1234 is the owner of the gitlab above

Yeah, that's me. I tried a few things at the request of the owner of this repo several months ago, but unfortunately doing so without hands on the hardware makes things really difficult and it didn't really go anywhere. Maybe come October if a bunch of them end up on second hand markets for cheap, I'll be able to get ahold of a full unit. Though not sure I'll have a place to put one at this point...

The main issue with booting anything based on the shield devices is that the jamboard is booting a 4.4 kernel and the kernel device tree isn't fully compatible with the 4.9 kernel currently in use by foster. Combined with google never releasing kernel source for the jamboard. If someone was able to make that latter happen, I could probably make something happen. But I either need a proper source release or a dump of the DTB partition. Without either, stuff is difficult.

bbf commented 2 weeks ago

Disclaimer: I'm not a lawyer so I can't make any assertions, and neither does my opinion here reflect the opinions of my current or previous employers. =)

Although if Google seems out of compliance by not sharing the source tree used to produce and distribute the binary used in the Jamboard, I might know a contact that perhaps will be able to help. I have to check if they are still at Google, since I left 2 and 1/2 years ago. Let me reach out to see if I can get the ball rolling. I'll update here as soon as I have any news.

bbf commented 2 weeks ago

Well, Chris DiBona who used to run the OSPO inside of Google left in 2023, so I don't have a direct contact right now. Let me dig further and I'll see if I can find an alternative.