How to build recovery for Peloton Tablet?

[sagz]

I know this repo has been inactive for ~2 years, but... I'm trying to get root or any custom recovery working on a Peloton 21" RB1VQ Tablet which is an MT8173 chipset armv8l

Here's some more device info from ProjectConfig.mk and build.prop file at https://gist.github.com/sagz/64dbe6611e23da7084fe7b0b6f2da1a7 (There's also fastboot getvar all output there in the comment of the gist)
Also, they seem to have posted their kernel here: https://github.com/pelotoncycle/opensource-ruby/

Bootloader is unlocked and I tried a bunch of things and learnt that it doesn't have a recovery partitition and uses a recovery-in-place logic. I also tried mtk-su from https://www.xda-developers.com/mediatek-su-rootkit-exploit/ but this tablet is patched with August 5, 2019 Android Security Patch.

Any tips on how I can try a 'generic' recovery image since bootloader is unlocked? maybe the getvar dump in the gist might help you assess?

[rydeordive]

Hey - did you ever figure this out? I have a Peloton tablet stuck in a bootloop and the company won't help me at all with trying to recover it!

[sagz]

Haven't figured it out yet. What part are you stuck at? Maybe we can help each other.

[rydeordive]

Hey - here's where I'm at below. I'm not really savvy beyond this tech-speaking though in terms of code/etc.

I usually leave my Peloton on but I powered it down as I was leaving for a week. When I got back and powered it back on, I'm stuck at the Peloton White Logo, which occasionally disappears, acts like its loading and then re-appears basically stuck in a boot-loop of some sort.

I'm unable to use POWER + VOLUME UP to get to the fastboot menu. I've done a static discharge and attempted to access fastboot multiple times.

I can do POWER + VOLUME DOWN to get to the fastboot to display in the bottom left, but nothing happens.

I've also tried to use ADB to pull the Peloton up but while it seems like the tablet attempts to connect at some point, I've not been able to get it to display via adb devices.

It does show via "fastboot devices". But if I do "fastboot reboot recover" I just get an error. It seems like its just corrupted at the bootloader level and can't get past that? When I do fastboot reboot recovery, it resets the tablet but just comes back around to the white logo again I think. I also can't get oem unlock to work.

It seems like the corruption must've occurred right upon boot and before whatever loads the ability to access via adb as the tablet doesn't exist there. It does via fastboot though but then gives the error with the recovery command. Here's what the error message looks like: imgur.com/RQ6J46p

Anyone have any suggestions on how to potentially access and get it reset back to the original firmware?