Share this Story

CM9 Inches Closer to Verizon’s Locked Galaxy S3, Kexec Boot Sequence Created

Rather than focusing on the negative aspect of the locked bootloader that accompanies the Galaxy S3 on Verizon, developer CVPCS decided to figure out a way around it. Using kexec, which has become synonymous with signed bootloader devices, he has created a boot sequence that allows you to flash custom kernels to the device, leading to CyanogenMod compatibility.

In a Google+ post released this morning, he breaks it all down. 

So for anyone who is wondering, this last weekend I finalized a kexec-based boot sequence for CM9 on the d2vzw (Samsung Galaxy S3, Verizon variant) that will allow standard installs to the device.

All of the kexec internals are now stored on the system partition, and cold booting into the stock kernel will result in the following:
1.) boot is hijacked immediately after the filesystems are mounted
2.) kexec-boot.zip is copied to /cache and set to auto-flash on reboot
3.) device is rebooted into recovery
4.) kexec-boot.zip is auto-flashed without user interaction
5.) device is kexec-rebooted with androidboot.mode=kexec
6.) boot is not hijacked since it is within a kexec environment
7.) the system is now booted with a custom kernel

This means we now have custom kernels that can be booted directly from a cold boot (no booting into recovery and flashing a zip manually, that will be done for you). Also this means that all of the kexec internals are on the /system partition, so backups and restores from recovery function as expected. The only downside to this is that the boot process actually involved 2 quick reboots, but it’s preferable IMO to having to flash manually from recovery.

The main problem still existing with the device is the lack of data connectivity. This is currently being looked into. Voice calls and SMS function as expected, but the SIM appears to be failing provisioning resulting in no 3G/4G connectivity.

I’ll keep you posted.

As you can see, there is a problem with the SIM and radios, which Austen does not believe to be because of bootloader situation. It sounds like they should be able to fix it in time.

Locked or unlocked, the devs are coming through in magnificent ways.

Via:  Google+

Cheers Steve!

  • Ryanerikk

    I don’t understand how to do any of this to my phone S3. If possible who knows how to get my phone to this point do I can add CM10 just released today. It’s unofficial but willing to give it a try and get rid of touchwiz.

  • I’m fimiliar to rooting but not to Kexec, and I have a question to anyone who is fimiliar to it and to the Droid X development.

    Should I buy the Developer Edition of the GSIII, or will this Kexec thing make it to where there are plenty of ROMs for the current locked down device?

  • I don’t know much about how easy this is to bypass, but I like to flash ROMs and I like to have lots to choose from.

    Knowing this about the workaround for the bootloader, would you guys recommend staying with my current Galaxy S III with the locked bootloader, or selling it and geting a Developer one?

    • J Dub

      I don’t know how much support there will be for the developer model. I’m not going to shell out $600 just for the principle that Samsung should have said “No” to signinglockingencrypting the bootloader in the first place.

  • no

    seems halfass I want a full blown unlock 🙂

  • tgom222

    The Verizon GS3 development is actually coming along rather quickly. The thing has been in stores for what, 5 days and it had already been rooted, custom recoveries and debloated custom ROMs. I flashed a ROM on mine that someone pulled from a Sprint GS3 that gives you the 50GB Dropbox space that Verizon and AT&T opted out of. Then I just Nandroid back to my rooted stock ROM until I can get CM9/10 or AOKP. The Dropbox space stays with you account.

    Screw Verizon! If Sprint had decent coverage around me (or if I didn’t have an unlimited plan) I’d switch.

    • Where did you get that rom with the Dropbox storage? Thats one of the big things I wish i had, especially when I might get a Nexus 7 which has very limited storage.

      • tgom222


  • nightscout13

    will CVPCS be the one to claim the bounty?

    • J Dub

      The bounty is for actually unlocking or patching the bootloader if I am not mistaken. Not the Kexec method.

      • nightscout13

        Well, a flashed bootloader from the dev phone would qualify, no?

        • Rickrollo

          No, you would still have the signed bootloader. You can’t wipe the original bootloader until you gain access to it. The bounty is for hacking the bootloader, not flashing another bootloader in a partition.

          • nightscout13

            No one will fully hack the bootloader. It’s encrypted right? How many encrypted Bootloaders have been fully unlocked? None as far as i remember. The previous Bootloaders have workarounds, such as the Motorola devices, but they are not fully unlocked.

  • J Dub

    All hands on deck to get this buttoned down before VZW forces an update onto the phone and puts everything back to square 1. Patiently waiting the day I can get rid of the stupid behind the scenes crap VZW installed like the constant wifi searching and popups. Once CM9 gets loaded I will truly be happy with this phone.

  • AryanRich

    come chat bitches http://tlk.io/Droid_Life

  • Destroythanet

    Devs > Verizon all day long!!

  • Scott Souder

    Yeah! Fu** Verizon!

  • zepfloyd

    And boom goes the dynamite.

  • Me

    Is there something like this for the Razr??

  • T4rd

    It’s only a matter of time before they break this open and send a big F-You to Verizon. As big as this phone is and the bounty on its bootloader, I’d be surprised if it wasn’t cracked in the next week or two. I like to think Samsung only signed (not encrypted like Moto does) the bootloader because they wanted to give us a chance to unlock it too.

    • Hyuk

      Does Samsung even know how to do encryption? Moto’s been doing it for years for the military, but I don’t think Samsung could encrypt a bootloader if they wanted to. All the better for us I suppose.

      • michael arazan

        At least its not as bad as apple that had kill switches for every iphone if it was jail broken or unlocked they could kill the phone and wipe it. That’s even worse that a company would do that to the consumer who bought their product.

  • Philip Van Luke

    Should I buy this instead of a CDMA galaxy nexus? I really want a nexus but the numorous reports of a variety of problems are making me worried. are mic dropout, low speaker volume, and random reboots really as bad as the internet makes it out to be, or is the nexus still a better choice than a GSIII?

    • Philip Van Luke

      I’m finally ditching my thunderbolt which I HATE HATE HATE, and I dont want to get stuck with another broken phone that I cant stand using.

      • I never had a single problem with my Thunderbolt. I’ve been running Thundershed on it since it was available. Part of me misses it but this GS3 is effing boss.

        • kilbasar

          No part of me misses the tbolt. The battery life was abysmal (even with the best kernel/ROM/radio combo you could find), and so far I get 2x battery life on the GS3. Carrying around spare batteries just because my phone couldn’t last half a day was silly. So far I love the GS3, running the rooted/stripped ROM, it absolutely flies.

      • 2cents

        The customizing(roms) options that can be done to the Galaxy Nexus are simply amazing. If your getting an S3 on Verizon it is limited for now, but likely won’t be for long. I have a G-NEX that survived a roll over after flying out of the car so mines disaster proof. The S3 is a fine phone and will most definately be an exceptional phone when some AOSP roms get on it. Officialy a Google Experience phone will typically get new OS’s first. The Xoom for all the 20 that were sold is about to get Jelly Bean and within a short period G-Nex’s will be getting some Jelly Bean. Personally I think from tests I’ve done that the G-Nex screen looks better testing with exact high quality wallpapers. Does the G-Nex have draw backs sure. I’ve seen the folks here running there S3 battery out while my stock battery keeps chugging beyond the S3. You can always give a test drive. Unlock, root ROM… Then reverses if your not happy with what it provides. By the time you decide hopefully all the kinks are worked out with the locked bootloader on the V S3.

      • J Dub

        Personally IMHO the hardware is way better on the S3. The chipset is much newer technology. I will just have to patient and know that before too long there will be a custom ROM that will make this a perfect device. It won’t be as open as the G-Nex, but I think I’ll take the hardware of the S3 over the G-Nex. Software can be fixed. You can’t redo the hardware.

    • sc0rch3d

      get the GNEX….huge support already exists and ready to go. played with my GNEX next to my boss’s S3…you can hardly tell the difference in size and slimmness and performance. i’m also a “stock” fan and touchwiz greatly annoys me (i’m sure that will be cracked and removed shortly if not already).

      however, if you do not plan on rooting and custom rom’ing…go with the S3

      • philip van luke

        I would rather have the option to bake my own android versions because i like to tinker. but again, all the tinkerability in the world isnt worth it to me if the basic functions of the phone are broken. so i ask again, is the mic volumn really that bad, because i use my speaker phone functionality alot. and if mic drop out and reboots are really a problem i dont want anything to do with that.

        • sc0rch3d

          no mic or speaker problems here. i can typically take a shower, put pandora on, and still hear it reasonably well 10 ft away. if i’m on a conf call, i typically have to turn down the speaker. no one has said i have mic issues. i did have to use a custom kernel to boost ear speaker volume only b/c i’m slightly deaf and any road noise makes it difficult to hear while driving.

          i have only seen random reboots when i flash something incorrectly. can’t testify very well since i was only on stock the first 3 days the phone came out, been on custom ROMs for the last 8 months. stick with a good dev and typically you won’t have basic functionality issues.

      • freeze

        Are you high??

    • T4rd

      Depends on your situation; if you’re going to to buy on contract and don’t care much about rooting/ROMing (for now), then get the GS3 because it’s not much more on contract. If you’re buying off contract (used preferably – I see VZW Gnex’s go for around $300 pretty often) and you do like to run custom kernels/software, then definitely get the Gnex. I haven’t experienced any of those issues you mention on my Gnex though, stock or rooted. Well besides the low volume, but that’s easily fixed with Volume+ if you’re unrooted and it’s fixed in most ROMs by default.

    • Sean Wood

      Coming from a Nexus to an S3 myself… so far.. the hardware spanks the nexus… there are a few issues with software that involve Verizons meddling that actually make me want to get my Nexus back from my daughter, but if this flashing method comes to full
      fruition you can easily overcome them with a new rom.

    • Bsody

      The only GNex problems I have had was random shutdowns, though I just discovered it was because of the kernel I had on it. Ive never had another issue, for what its worth.
      The GSIII is obviously a beast, so you really cant go wrong either way.

    • archer

      the nexus is no worse in those areas than other phones ive had, and i absolutely love mine. if you live in a popular area, dont worry about reception. out in the country, then you may want to consider another.
      low speaker volume is a minor concern, the random reboots are not (maybe twice in a year? other phones have been worse).

      these few complaints don’t compare to the disappointment from the modifications samsung did to the android UI on the GS3

    • usty

      Went from the Nexus to the S3…had it about a week now. Loved my nexus but slowly getting used to the S3. Installed nova launcher and beautiful widgets to get rid of the touchwiz crap (and bring the stock ICS folder style) the battery life on it beats the hell out of the Nexus which is why I’m probably going to hold on to it. Figure there’s enough volume out there that the developers will eventually make strides in the ROM area.

      Though I do have to say playing around with Bugless Beast 4.1 on wi-fi only with my Gnex is really nice. JellyBean is awesome.

      • Lakerzz

        ^ This

    • The Mic problem is very real. My wife gets so frustrated nearly every time she calls me because she can’t hear me after a few minutes

    • nhizzat

      If given the choice right now, I’d choose the Galaxy Nexus only because of the current dev support. If the SGS3 had an ICS or JB AOSP rom available now, I’d choose the SGS3 every time. I don’t care for kernels and the battery life of the SGS3 is fantastic.

      I have yet to experience any of the issues you mentioned with my Galaxy Nexus. The hardware of the SGS3 is leaps and bounds better than the Galaxy Nexus and it won’t be long until there’s CM10 or just any ICS/JB AOSP rom available to flash.

      And Touchwiz is just awful…

      • J Dub

        The phone has only been in the hands of the masses for a week and that’s only those that pre-ordered. You can’t expect AOSP ROM’s that fast. The Nexus got JB so fast because well…it was built first for the Galaxy Nexus from Google.

    • brandon

      I had the galaxy nexus And it had many issues the signal was bad and a loud click sound would come from the processor not the speaker. It was bad and only during calls the gs3 is much better

  • HoNz


  • p_droid

    What an awesome dev. He is the reason the Droid X developer community exploded after being pretty small due to the locked bootloader. And now he’s at it again! Bravo.

    • trophynuts

      Agreed. I remember his work on the DX very well. good stuff.

      • the droid x community was already huge from day 1 because it was viewed as a challenge…however it did continue because of his work

        • Droosh

          I credit him directly with 2nd Init. Before this there were no AOSP ROMs at all. Just derivatives of Stock.

  • WCDave

    That’s what makes Android great – a community which comes up with solutions for everything!

    • Big Gay Al

      u know what else inches closer to my gs3? take a guess hehe