Comment by zozbot234
12 days ago
Yes, though noting that since the antirollback is apparently implemented by the bootloader itself on this Qualcomm SoC, this will blow the fuse on devices where the new version is installed, so the unofficial EDL-mode tools that the community seems to be most concerned about will still be unavailable, and users will still be unable to downgrade from the newer to older custom ROM builds.
> unofficial EDL-mode tools
The linked page seems to indicate that the EDL image is also vendor signed. Wouldn't that mean they're official?
Unless I've misunderstood, the EDL image is tied to the same set of fuses as the XBL image so it's only useful to recover if the fuses don't get updated. Which seems like an outlandish design choice to me because it means that flashing a new XBL leaves you in a state where you lack the fallback tooling (hence the reports of people forced to replace the motherboard) and also that if there's anything wrong with the new XBL that doesn't manifest until after the stage where it blows the fuses then the vendor will have managed to irreversibly brick their own devices via an only slightly broken update.
EDL itself is a huge hack anyway, so who knows. The underlying issue is that the OS suppliers are forced to bundle what is effectively the equivalent of a BIOS (low-level firmware) with their image (because of the underlying assumption that this is an embedded system where there are no third-party OS suppliers), and the "BIOS" update has to be made a one-way street when the older firmware has vulnerabilities. Newer EDL tools ought to become available but they might not have the exact same capabilities as the older ones, though they'll most likely be usable for basic recovery.
Not being able to downgrade and using the debug tools was the exact point of doing this thing, as far as I understand.