Meta defined the precise technical motive that some Quest headsets had been bricked late final month.

For those who missed it, in December some Quest headsets, mostly Quest 2 headsets, stopped booting efficiently, getting caught in what’s referred to as a “boot loop”. The problem occurred after an automated firmware replace for headsets which hadn’t been up to date in a very long time, the place the distinction between the beforehand put in model and the most recent replace was important.

By the top of the month, Meta had acknowledged the difficulty and instructed prospects “typically, you at the moment are in a position to make use of your gadget usually”. For gadgets bricked, the corporate began providing free replacements, even out of guarantee.

Now, three weeks later, Meta’s VP of Quest and Horizon OS Mark Rabkin is detailing precisely what occurred.

Rabkin says the difficulty was a “uncommon race situation in AOSP R/W ext4 filesystem that corrupts recordsdata + a key safety patch that forestalls OS rollback”, saying that the bug has been there for 4 years however hasn’t been a problem till December. Additional, in keeping with Rabkin, a safety patch prevented the OS from rolling again to a working model.

AOSP is the Android Open Supply Challenge, the open-source core of Meta’s Horizon OS that runs on Quest headsets, ext4 is the Linux file system that Android makes use of, and R/W refers to studying and writing from the file system on the identical time. A race situation is a matter which might happen in multithreaded software program when totally different components of the code working alongside one another execute in an sudden order, resulting in an unanticipated final result.

Basically, Rabkin is claiming {that a} bug in how Android’s file system handles studying and writing on the identical time in a really particular and uncommon situation triggered the difficulty, and a safety patch supposed to stop rolling again to the earlier OS model left this defective replace in place.

Meta Servers Damaged, All Quest Headsets Unusuable

Meta’s servers weren’t working accurately earlier at present, and the difficulty rendered all Quest headsets quickly unusable.

It is the most recent in a historical past of outages from Meta, and for these affected, way more severe than any previous problem. Again in 2018 each Oculus Rift stopped working as a result of an expired certificates. That downside took Meta (then Fb) greater than 12 hours to repair. Extra not too long ago, each internet-connected Quest headset stopped working for round an hour in March 2024 as a result of a server error, resulting in Meta vowing to make Quest headsets “extra resilient” to server points going ahead.

The bootloader of shopper Quest headsets is locked, that means you’ll be able to’t manually flash a customized working system, and Meta does not permit you to downgrade to an older Horizon OS model both. These selections depart the gadgets susceptible to a problem like this, though the situations wanted for one to come up are exceedingly uncommon. To be seen as a severe shopper electronics firm on par with Apple, Meta could should rethink a few of its insurance policies on software program updates, and construct up the type of belief that’s considerably eroded by being left with a brick on Christmas day.