WHy does downgrading not work?
- Thread starter knitler
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D
Darth
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Or, you can downgrade... But brick your device after, even later.
Anyone who knows anything about the moto x will tell you just don't. ?
Anyone who knows anything about the moto x will tell you just don't. ?
I find that odd. I wonder what the purpose is for doing that.
There is no way to just re-write those sections? Even on a Dev Edition?
There is no way to just re-write those sections? Even on a Dev Edition?
Security!
Look at the whole Windows/AntiVirus industry.
All because Microsoft wanted unsecure compatibility with the old OS.
Saving software dev time making things work.
D
Darth
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No, the Dev edition is no different. All the same "rules" apply.
The Dev edition is the same as any other.... It just keeps is warranty if you unlock it.
I'm kind of not buying this for a second?
How about linux, which is often pointed to for its security... And you can upgrade, down grade, switch out every component for newer/older/different, switch kernels, upgrade kernels, downgrade kernels... hell change out kernels with out even rebooting.
Really not buying it has anything with security.
I think we understand that, I mean if the OP didn't he wouldn't have the question of "why not?". Its not I think it might be a good idea... We are just trying to understand the situation because it seems unique, and so we were hoping someone who knows a lot about
This is the most I have heard so far, and I have heard it once or twice... But can't the recovery image include information on the partition table?
I realize the way it is, but was curious on some more technical information explaining it...
It is security. Specifically the SECURED BOOTLOADER. Don't confuse secured with locked. Yes, you can unlock your bootloader, but it is still secured.
Read up on "TrustZone" and see why it is important, and why the OEMs would not want you to be able to downgrade. You can "buy" or "not buy" whatever you want....
I really don't get the linux reference. We are talking about a bootloader, not linux in general. That's beyond the fact that any smart linux user would almost never have any reason at all to downgrade. Think about the heartbleed vuln that was discovered recently. Why on god's green earth would you want to downgrade openssl back to a version that is vulnerable??
The early (4.2.2 & 4.4) bootloader (motoboot.img) was vulnerable to an exploit that allowed us to disable write protection. The updated bootloader (4.4.2+) is patched. You *CAN NOT* downgrade back to the vulnerable version.
^Does that not have *everything* to do with security??
Because even though the patition file and bootloader are included in the archive, they fail to flash because they have a lower version than what is installed.
The linux reference was in direct reply to the quote above it that was making the argument that the PC anti-virus industry as well as the proliferation of malware and viruses is an example of the insecurity that is a result of a computers administrator having the technical ability to downgrade his OS software.
I mention linux because he was using PC OS's as an example, and Linux allows you not only to downgrade... but rewrite the bootloader. Or use a different bootloader. You bootloader can boot securely with UEFI, or you can just use BIOS. All this insecurity, but virtually no viruses, and very few security issues.
Why would you want to downgrade openssl? I wouldn't. I probably wouldn't flash back to an earlier version of android either... I keep my system pretty damn up to date. The point is more that his assertion that MS and Windows proves that being able to downgrade creates inherent security issues doesn't really hold up when you look at other systems that provide even more freedom.
I know, and that is why I want to understand what it is I would be buying.
I guess this is the part that we are not understanding. Perhaps because I don't understand enough and have not looked through decompressed recovery images enough... but basically the issue is that Motorola is bricking the device, rather then letting it be downgraded to an potentially insecure image. I am guessing then this is a soft brick?
Does recovery not have the ability to re-write the partition table though? Is there no partition table information in this recovery image? I get that the stock recovery would not allow it, but wouldn't a developer edition user be able to flash a custom recovery that wouldn't have issues flashing the partition table. Don't TWRP or CWM, ect do this?
I guess then that is where the trust zone comes in...
The custom recoveries don't flash gpt.bin nor motoboot.img so using a custom recovery it's impossible to correctly flash a Moto X. You MUST use stock recovery with a Moto X. The problem isn't that it causes a brick by flashing an old version. The problem is that a brick happens the next time you do an OTA update. When the OTA update occurs there is a mismatched partion table and bootloader, so it ends up causing a brick.
The developer edition and the standard moto x are 100% identical. They only difference is that you don't void the warranty when you unlock the bootloader on the dev edition, however with the non dev edition your warranty is voided. So the same problem with the partition table and the bootloader ALSO apply to the developer edition as well.
Still the answer is security.
So upgrade as Moto intended & do not downgrade!
---------- Post added at 07:37 PM ---------- Previous post was at 07:30 PM ----------
Our recovery devs never restore such partitions or boot loader elements.
So upgrade as Moto intended & do not downgrade!
---------- Post added at 07:37 PM ---------- Previous post was at 07:30 PM ----------
Our recovery devs never restore such partitions or boot loader elements.
Smh I normally don't chime into these threads but I had to, you can't downgrade the bootloader because of security/compatibility plan and simple. It's the same concept as why you can't downgrade most PC's bios, if there is a flaw found in the system as a whole, then they don't want you to downgrade to that version. A lot of the times when people brick their device trying to downgrade is because it will flash, but because an efuse was blown when it was upgraded the downgraded version will not boot. Yes the recovery can technically rewrite those partitions but again because the efuse was blown it will not boot. Also yes being able to downgrade on any system Windows, Linux, Unix, IOS, Xbox, PS, etc are causes to security issues. If you can downgrade a system to a vulnerable version, it is then by definition less secure, no matter how you try to spin it. Take the futex vulnerability which affected most linux kernels from the past 5 years, so why would any desktop linux user ever want to downgrade to a vulnerable kernel? They wouldn't but if the end user isn't knowledgeable of the vulnerability they wouldn't know that downgrading makes them vulnerable. So since phones are used by so many people who are not knowledgeable of vulnerabilities, why would you want to give them the opportunity to downgrade themselves to a vulnerable OS?
Appreciate the info given... I don't want to downgrade, I am not trying to downgrade, I understand why its a bad idea, ect...
My view point was more questioning the insistence that it being technically possible to downgrade creates a security flaw on a machine that is kept up to date by a responsible individual. Unless we are trying to speak more abstractly about that fact that given someone the opportunity to make a mistake makes it more likely for one to occur, I don't think that security threat exists until you actually use that ability to downgrade to something with a flaw.
I guess then it comes down to personal viewpoint of do I want my phone to brick it self to protect me from myself and like sam said, you choose to go elsewhere... But then that is somewhat what I am trying to figure out. Even though its not something I would probably ever have to deal with, I don't like the idea... But "bricking" can be such a vague term with manufacturer specific recovery tools and "different levels of bricking".
Just trying to understand how what and when actually happens. I probably need to read some more of the recovery threads, and I have been looking through old threads here while considering VZ dev moto X and waiting for the x + 1 announcement, but I figured I would jump on the thread while it was here.
I understand keeping it simple because its generally a bad idea all around, and its just best not to confuse things... but its been hard to find deeper discussion or information then the general warnings. A bit of a better picture from this thread though.
By "Our recovery devs" do you mean the ones doing the moto specific stuff? Do you know if this Is typical of the custom recoveries for other devices?
My view point was more questioning the insistence that it being technically possible to downgrade creates a security flaw on a machine that is kept up to date by a responsible individual. Unless we are trying to speak more abstractly about that fact that given someone the opportunity to make a mistake makes it more likely for one to occur, I don't think that security threat exists until you actually use that ability to downgrade to something with a flaw.
I guess then it comes down to personal viewpoint of do I want my phone to brick it self to protect me from myself and like sam said, you choose to go elsewhere... But then that is somewhat what I am trying to figure out. Even though its not something I would probably ever have to deal with, I don't like the idea... But "bricking" can be such a vague term with manufacturer specific recovery tools and "different levels of bricking".
Just trying to understand how what and when actually happens. I probably need to read some more of the recovery threads, and I have been looking through old threads here while considering VZ dev moto X and waiting for the x + 1 announcement, but I figured I would jump on the thread while it was here.
I understand keeping it simple because its generally a bad idea all around, and its just best not to confuse things... but its been hard to find deeper discussion or information then the general warnings. A bit of a better picture from this thread though.
By "Our recovery devs" do you mean the ones doing the moto specific stuff? Do you know if this Is typical of the custom recoveries for other devices?
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The thing is you keep looking at it from a PC point of view, where you basically have full control over the software and hardware. Phones have much tighter restrictions on them from carriers, fcc, etc they're not personal computers. So the reason they make it where you can't downgrade the bootloader is because that's what controls the restriction on downgrading any other partition on the device.
So with the Moto X's 4.4.4 update they probably blew an efuse, so users with a locked device can't downgrade. This is done because with locked devices they can only flash signed kernels, so by blowing the efuse they can't downgrade to the vulnerable 4.4.2 and below kernel even though it is signed correctly. This is because lets say a malicious app was able to get on a device that had the ability to downgrade say back to 4.2.2. That app could flash the older vulnerable signed kernel to the recovery partition, to disable write protection gain more control over the phone etc, without the users knowledge. Now that is a stretch and probably will never happen but that doesn't mean the threat isn't there, and hackers are very creative at deploying malicious attacks. So by updating the bootloader and blowing an efuse the older vulnerable kernels can't be flashed. Now this is all negated if you're unlocked of course, but if you don't want to ever worry about this issue don't update your bootloader. This is not recommended but I've mentioned it several times on this forum I haven't updated my X's bootloader since I bought it, it's still running the factory 4.2.2 bootloader, running 4.4.4 with no problem.
The other thing you're missing is we're technically not supposed to have the ability to restore our phones, except for the developer edition of course. The fastboot restore files are leaked not released to the public, they are designed for use when phones are returned to be refurbished. So they don't want the phones that are being refurbished to be flashed back to an older version, they want it to be refurbished and the latest software version flashed to it.
A bit selfish, and perhaps lazy of me but I am only really here talking about the developer version, I just haven't bothered to write the full "verizon developer edition " every time (most of this is research for next phone, which will be developer handset)... To me, obviously a locked phone is going to have weird restrictions and hacked together paths to getting things done, your not supposed to have admin rights...(yeah, maybe I do look at it too much as a computer. Mostly because I am annoyed the differences seem intentionally imposed). But when I pay outright for a device so that I can own it and have full administrative control... anyways, thats a different more philosophical discussion. The point is I have been talking about an unlocked device using third party software where possible.
Either way, appreciate the reply. I have a better understanding of the issue... Though coming from an S4 it still seems weird that MDK*/developer phones don't seem to have the same issues/warnings. It would seem however that the difference may be that MDK/dev owners only use kernels/roms prepared for their devices and do not update the bootloader. I suppose if more people in the Moto X community were worried about maintaining the ability to downgrade an unlocked device it would be technically possible to upgrade in a way that could be easily reversed, similar to the S4.
(*MDK was the first VZ S4 firmware, and the only one that has a released exploit to allow for a full custom recover. Later locked firmwares must rely on safestrap)
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The custom recoveries don't flash gpt.bin nor motoboot.img so using a custom recovery it's impossible to correctly flash a Moto X. You MUST use stock recovery with a Moto X. The problem isn't that it causes a brick by flashing an old version. The problem is that a brick happens the next time you do an OTA update. When the OTA update occurs there is a mismatched partion table and bootloader, so it ends up causing a brick.
The developer edition and the standard moto x are 100% identical. They only difference is that you don't void the warranty when you unlock the bootloader on the dev edition, however with the non dev edition your warranty is voided. So the same problem with the partition table and the bootloader ALSO apply to the developer edition as well.3
Smh I normally don't chime into these threads but I had to, you can't downgrade the bootloader because of security/compatibility plan and simple. It's the same concept as why you can't downgrade most PC's bios, if there is a flaw found in the system as a whole, then they don't want you to downgrade to that version. A lot of the times when people brick their device trying to downgrade is because it will flash, but because an efuse was blown when it was upgraded the downgraded version will not boot. Yes the recovery can technically rewrite those partitions but again because the efuse was blown it will not boot. Also yes being able to downgrade on any system Windows, Linux, Unix, IOS, Xbox, PS, etc are causes to security issues. If you can downgrade a system to a vulnerable version, it is then by definition less secure, no matter how you try to spin it. Take the futex vulnerability which affected most linux kernels from the past 5 years, so why would any desktop linux user ever want to downgrade to a vulnerable kernel? They wouldn't but if the end user isn't knowledgeable of the vulnerability they wouldn't know that downgrading makes them vulnerable. So since phones are used by so many people who are not knowledgeable of vulnerabilities, why would you want to give them the opportunity to downgrade themselves to a vulnerable OS?1
Because even though the patition file and bootloader are included in the archive, they fail to flash because they have a lower version than what is installed.1@scryan
I know far less then other posters, but yes android recoveries are all very similar in that regard.
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