Edit (11/2/19): This post was updated to clarify and add information on more of Apple’s repair apps.
No mere mortal, lacking Apple’s stamp of approval, can completely fix the company’s products. You can do a lot, but in the newest iPhones, you can’t restore Touch ID, install a new battery, or replace a screen without a warning. Trying to replace core Mac parts can trigger a lock-out. No sacrifices or incantations can overcome this.
Instead, Apple’s official repair procedure requires proprietary software tools, available only to Authorized Service Providers and members of Apple’s unlaunched Independent Repair Program. We’ve previously written about Apple’s internal diagnostic software, which Right to Repair legislation aims to make available to the rest of us.
What, exactly, can Apple-approved folks do with all this secret software-that-shall-not-be-named? Let’s dive into what we know. And take a look at Samsung’s own secret repair app, while we’re at it.
Apple’s Cloud-Based Diagnostic & Calibration Tools
First off, Apple’s diagnostic software has a name: Apple Services Toolkit 2, often abbreviated as AST 2. Once you know that, you can find it mentioned and even pictured in many places: on Apple’s own discussion forums, on PDFs inadvertently posted publicly by university IT help desks (ahem), or even in the dark corners of YouTube.
You can only access AST 2 with an active connection to the web, and an authorized account with Apple’s private Global Services Exchange, or GSX. With an account, and certifications installed on your MacBook or iPad, you can then service Apple devices. You need a device’s serial number, which can be either read off the device in front of you or given to you over the phone. This remote connectivity is how Apple Store employees can check devices on the store floor, without lugging around cables or computers.

Next, you enter the category of problem you’re trying to fix: “Fan,” “Charging,” or the like. The device gets a request to allow a diagnostic tool to run. Presumably, there is a workaround for devices with entirely broken screens, likely involving a USB cable, but we haven’t seen it in action. After the access request is approved, a diagnostic tool checks everything: battery, Bluetooth, cameras, sensors, Touch ID, the works. Pretty neat!

AST 2 can show you what’s wrong with a device, along with a lot of details you can only see if an Apple Store employee is feeling cavalier and generous. One thing to note is that AST 2 provides a cycle count for an iOS device battery. Cycle count is important information that every device owner should have! Unfortunately, Apple has banned apps from their App Store that show cycle counts for mobile devices, creating a cottage industry for apps like Coconut Battery.
AST 2 is (perhaps obviously) not the first diagnostic app that Apple has made—AST 2’s precursor was a totally different tool, and it’s still used to fix older devices, mostly from 2013 and earlier. You can see AST 1 (technically 1.5) in action in this Italian video of a MacBook Air repair.

If something needs fixing or replacing, Apple’s equivalent of iFixit guides are available through the GSX site (check the left-hand column in this screencast). Apple’s Authorized Service Provider Manual notes that GSX grants you access to “take-apart, upgrade and repair procedures, basic servicing information, troubleshooting flow charts, product specs, adjustment procedures, and exploded view diagrams with part numbers.” That all certainly sounds like useful information!
AST 2 isn’t just helpful, it’s mandatory. Apple technicians cannot order parts for an Apple device until they’ve run a full diagnostic on the device at least once, even if they already know what needs fixing. And newer Macs with T2 security chips will not function until a full diagnostic has been run on them after the repair.

After a hardware repair, newer Macs with T2 chips require that a separate program, Mac Configuration Utility (MCU), be run while connected to another Mac via USB or Thunderbolt cable. This re-enables parts like logic boards, top cases, Touch ID, displays, and flash storage. Without doing so, a Mac’s screen will read “Waiting for session,” and will not function until the MCU is paired and executed. A similar tool, RepairCal, is needed to re-enable batteries, Touch ID, and screens on newer iOS devices.
Apple has sworn everyone with access to secrecy (with the exception of a few helpful/careless public posts). According to Apple’s Authorized Service Provider Manual, a basic requirement of being an authorized Apple tech is that “Apple’s repair and screening process must be kept confidential and can not be disclosed or visible to any third party, including customers in the service location.” That secrecy is helping no one. It prevents competent repair professionals from doing work they would be perfectly capable of, and leaves Apple’s customers in the dark about their own hardware.
Samsung’s “Must” Toolkit
We know even less about Samsung’s diagnostic software, but it has similar functionality. Samsung’s software is mentioned on Geek Squad, mobile repair subreddits, and on XDA-Developer threads. The XDA forums reveal the app’s actual name, Samsung Galaxy Must, along with a (dated) screenshot.
We were able to see this software for ourselves with a behind-the-scenes tour by an authorized Samsung service provider. It is also quite full-featured: Samsung’s software can verify battery health, touchscreen calibration, whether the phone’s firmware or software has been unlocked or modified (i.e. “rooted”), and read an internal barometer to determine the state of its water resistance. According to the iFixit staffer who got the tour, that screenshot is out-of-date, but it gives you a sense of what tools are available.
Like Apple and Samsung, most manufacturers keep their calibration and diagnostic software secret, hiding useful features from their customers. In testimony opposing Right to Repair laws, these companies argue that releasing this software will undermine their security model. Apple notably told lawmakers in Nebraska that releasing this information would turn the state into a “mecca for hackers.” Testifying in Boston on Monday, expert repairer Louis Rossman shredded similar arguments made by tech industry trade groups.
But not everyone is so user-hostile: Dell and HP happily make their diagnostic software and service manuals available to the public.
Secret Repair Tools Are Ridiculous and Wrong
Access to tools that tell you what is wrong with a device, explain how to fix it, and retain functionality after a repair is precisely the kind of thing the world needs if we’re going to push back the tidal wave of e-waste threatening the planet. Right to Repair legislation is desperately needed to level the playing field between the digital haves and have-nots.
Farmers already face this problem, with some turning to cracked Ukrainian firmware and sketchy backroom deals to obtain the software they need to repair equipment. And Paul Luiz, an expert diesel equipment mechanic, told us that he experiences the same problem trying to access engine diagnostics.
It’s time we call out the shroud of secrecy surrounding these tools for what it is: yet another strategy of planned obsolescence, aiming to force us into either unneeded product upgrades or paying the manufacturer’s inflated repair prices. If manufacturers won’t release the repair tools we need, then we’re just going to have to pass legislation forcing them to.
If you know more about AST 2, Samsung’s Must software, or other sly/secret diagnostic apps, we’re open to tips. I’m [email protected], but we can move over to secure chat if you like.
23 Kommentare
I used to work for Geek Squad and used AST 1.0 a lot, and GS’s private tool MRI, and I was shocked when I found out that it only worked because we had the devices connected to our network, and that the clients couldn’t run those diags on their own. It’s such a basic and simple diagnostic tool. The literal only reason I can imageine to keep it private is purely to prevent consumers from being able to make informed decisions. it’s disgusting.
David - Antwort
They want us powerless and scratching our heads at these devices we’re sold as if they’re magic and only their amazing technicians can truly repair them.
doompod666 - Antwort
Ridiculous that you have to go into the Apple store and deal with these clueless people for something so basic.
Luke L - Antwort
It still makes me smile when I again here the ‘merits’ of using a Mac as the studio computer of choice - BUT all (especially TDM) recording systems had an external bank of Processors that did all the IT ‘Grunt’ (the actually running of the processor components like live recording, Virtual plugins etc.) - The G5/MacBook was basically a ‘pretty screen’ running just the graphics. Now we have Intel i7s multi-core processors and internal SSDs which do perform everything. Apparently Apple Senior Management and nVidia (who made the Graphics Cards) had come up with a great way to lever even more profit by reducing the solder by 50% on the GPU. If the Mac got too hot it started to melt the small amount of Solder, causing the GPUs to fail. A £300 repair job each when mine failed in both my Macbook Pro and iMac
Denny Tuckerman - Antwort
Apple did recall over a million units and replaced the GPUs from 2007-2011 for free. BUT (I don’t expect you to have heard about this) they had 2 fix strategies (1) ‘Quich Dirty Fix’ - they put the whole motherboard in an oven at 315⁰F for 10 minutes and the GPU somehow resoldered itself back to the motherboard (2) ‘Permanent Fix’ - they replaced all the dodgy graphics cards. BUT they tried out fix No. 1 first. This appeared to fix the problem but then 80% failed again after 3 months and they all had to be recalled again and Fix 2 was applied, replacing 800,000 GPUs.
Denny Tuckerman - Antwort
That sounds like the 2011 MacBook Pro GPU issue mine had that Apple techs at the time it occurred repeatedly refused to acknowledge or to repair free of charge even after multiple visits, all they did until it completely failed was to keep reinstalling MacOS and blaming it on a corrupted installation which being an IT professional myself and having built my own Windows based PCs and been through my own share of failed components with them over the years did seem rather fishy (before the official recall aka “repair program”), luckily I had EU law on my side and used a Sales of Goods to force them to pay for an authorised repair agent to perform the repair (a replacement main board), it’s been fine ever since.
Richard D -
I hope they aren’t using a normal oven. A “reflow” oven is precisely calibrated to heat and cool the board along a specified temperature curve so the solder can be melted (“reflowed”) without causing thermal shock to the components (which would break them). A consumer oven (designed for cooking food) has no such control and could easily damage any boards placed in them.
If the problem is due to cracked/damaged solder balls under a chip, this can often be enough to fix it. But if there are other problems (e.g. corrosion from liquid intrusion or parts blown by overvoltages) then it won’t work and may make the problem harder to properly diagnose and fix - often to the point that you may have to swap the entire board.
Lois Rossman has talked about this in several videos. Definitely worth watching. If guys like him could buy replacement CPU/GPU chips from Intel/AMD, it would save us all a lot of money and aggravation.
shamino -
My used Macbook was Not covered By the free recall - it cost me £300 to get it repaired locally. When it came back, mine then failed again after 3 months - this time the engineer put a new GPU in and I'm still using that MacBook daily after 12 years (this is how I found out about this total fiasco).
Denny Tuckerman - Antwort
These companies personify greed. The end user is just there to be ripped off by predetermined obsolescence. Now we can’t even fix their rotten hardware , bend gate etc - their design flaws but first they deny there is an issue. Then there is a class action against them (leadless solder), then back to the store over and over again - 3 times for that fiasco. Steve must be turning in his grave.
David Filmer - Antwort
“Customers” are ignorant and need a nanny called “president” or “government”. Government’s creation, called “corporation”, has a duty to protect its beneficiaries, so if one wants things to change, then they will have to stop operating in the capacity of “Customers” and or “volunteers” aka “consumers”; they will have to learn how to become a beneficiary. The government created the corporation, so it gets the tax benefit, because what it creates, it can tax out of existence if it chooses. - - - - if one wants things to change, then they must stop living as a child(“minor”) in need of a nanny/manny(“administrator” / “executor”) - - - - if a “person” goes to “court” with a “claim”, then they are a “minor” in need of an “administrator” / “executor” . . . . The End
RU Hunting - Antwort
Lol goodness, being a part of the mobile device repair/ break-fix industry for a decade now, this issue is ridiculous. I’m having trouble agreeing with the Government and president analogies to Corporate America as our entire economy is built on this principle called Capitalism. The very principle that makes us GREAT has red-tape at every turn. I don’t know if I’d go as far as opiniating the issue as if these organizations and corporations are Owned by our government. Enterprise and Capitalism are what built the lifeblood of this country and is actually our identity. Advocating for Right to repair is the most responsible and strongest opposition we can make and eventually will be the hammer that nails permanent policy change in our sector of gadget repairs. In the meantime let’s keep learning, sharing and playing the game of legislation, (maybe without thinking of ourselves as sheep lmao, what a far off post I am replying to, not even comparable to the discussion topic at hand.
ryanamenton -
ahem, capitalism is a farce that has become engrained in society too convince people that the ownership of discovery and process are property with actual enforceable limits on usage and availability… profitability is supreme to capitalists and %#*@ the logic if you don’t agree… ryan’s belief that the identity of our country is constructed from capitalist theory in action is childish nonsense… humanity has long been restrained by denial of shared knowledge for the benefit of some faction or another to profit from this policy… releasing the power to the people to be able to repair their own property is the answer and he is right about that so cheers ryan and good ideas should be freely exchanged without the capitalist restraints and secrecy… now will come the capitalist excuses for profitability and proprietary functions to explain their greed…
mike - Antwort
This idea is increasingly being applied to other repairs too.
My car has so many computers essential to its operation that it can only be properly serviced by a dealer with the right computer diagnostic tools.
It’s going to worse as we continue to install more chips in more equipment. How long before something as trivial as a washing machine bevomes unrepairable by anyone who cannot access the diagnostic tools?
Jeff Armstrong - Antwort
I’m saddened by this latest article. My iPhone is still chugging along. I want to get a semi-pro DSLR camera for my 50th birthday and was hoping the next generation iPhone would fit that niche. No can do. I guess my next phone will be a Nokia-dumb phone and a separate camera. Pity.
pneem - Antwort
Get a Librem 5. It wont satisfy the DSLR need, but it is a smartphone built to be Free as in Freedom.
QwertyChouskie -
MUST is old and not really used anymore. At uBreakiFix, Galaxy Diagnostics (usually abbreviated as GD) is used for pretty much everything. Only IMEI rewrites (for PBA swaps) use a different tool (not MUST or GD). The funny thing is, GD's existence isn't even secret: we are supposed to run IQC (Incoming Quality Check) with the customer and show them any warnings reported by the software (did your phone overheat 2 years ago? An app used too much RAM 5 months ago? Some other app used half your battery charge once?)
1/3
QwertyChouskie - Antwort
It looks like you can find the APK half of GD online (https://www.apkmirror.com/apk/samsung-el...), not sure if that will let you run checks or not without the computer half of GD though. (Also, I think 2.0.5.8 is the latest version of GD, the version linked here might not even support current devices.) But really, you shouldn't even need GD in most cases, because of the *#0*# diagnostic functionality built-in to Samsung devices. (https://android.gadgethacks.com/how-to/t...)
2/3
QwertyChouskie - Antwort
Some terrible pics pulled from a training PDF:
https://i.imgur.com/rqbOKEN.png
https://i.imgur.com/Ozc6qNw.png
https://i.imgur.com/SeAEWyQ.png
I'm not sure if I can really go into too many more details (NDA and all), but everything in this post is, to my knowledge, either supposed to be public facing, or findable with Google. I hope this is useful, or at least interesting.
QwertyChouskie - Antwort
Also found this video after further online searching: https://www.youtube.com/watch?v=EX-JPJ8h...
Note that it seems a different view mode is enabled than what is usually used (at least at UBIF).
QwertyChouskie - Antwort
It wouldnt be so bad if you could trust the “approved technicians” to actually do a good job, In my experience of over 50 years in the electronics industry, I have frequently been unfortunate enough to be at the mercy of incompetence and inexperience by authorized service providers (motor vehicles also come to mind here). Generally, given access to the right tools, I can do a far better job than most professional agencies.
Alan Barlow - Antwort
Remember when Apple put RAM and hard drive upgrade instructions in the users manual?
TheYootz Media Group - Antwort
That‘s how cars are, and it’s a pain.
There is some reason to this: some things should not be reconfigured without authorization, so people reselling the cars won’t be able to change milage, reset airbags, disable eco-features in the ECU etc etc.
In case of security chips in macs, there is no point in it security if anyone could circumvent it with publicly-available devtools.
Дмитрий Гужов - Antwort
Curious to see if we'll finally have access to their configuration tool tomorrow (21.06.2023)!
https://nr.apple.com/DH0l5U1xi0
Mickael - Antwort