Checkm8 Exploit Opens Door to Unpatchable Jailbreak on iPhone 4S Through iPhone X - MacRumors
Skip to Content

Checkm8 Exploit Opens Door to Unpatchable Jailbreak on iPhone 4S Through iPhone X

A security researcher who goes by "axi0mX" on Twitter today released "checkm8," which he claims is a bootrom exploit for iOS devices equipped with A5 through A11 chips, including the iPhone 4S through iPhone X, several iPad models dating back to the iPad 2, and the fifth-generation iPod touch and later.

trio iphones ios
This would be the first publicly released bootrom exploit since the iPhone 4 in 2010 and pave the way for a permanent, non-patchable jailbreak on hundreds of millions of affected iOS devices. Since the bootrom is read-only, Apple cannot patch this type of exploit with a software update.


The bootrom exploit has many other possibilities on affected devices, including downgrading iOS versions without SHSH blobs or APTickets, dual booting iOS, and running custom firmwares, according to jailbreak enthusiasts.

This is significant news in the jailbreaking community, as the last bootrom exploit known as "limera1n" was released by George "geohot" Hotz nearly a decade ago for devices with A4 chips and earlier, including the iPhone 4, iPhone 3GS, the third- and fourth-generation iPod touch, and the original iPad.

Popular Stories

iphone 17 pro max battery 1 year

Three Years of 80% Charge Limits on iPhone: The Results

Tuesday October 6, 2026 12:59 pm PDT by
Since 2023, Apple's newer iPhones have had an 80 percent charge limit for those who want to extend battery lifespan. Charging to 80 percent instead of 100 percent is supposed to put less stress on the battery, improving longevity. For the last three years, I've used that setting on my iPhone. I started with the iPhone 15 Pro Max, then did the iPhone 16 Pro Max, and most recently, the iPhone...
apple welcome home event

Apple Product Launch Announced for October 13: 'Welcome Home'

Thursday October 8, 2026 9:04 am PDT by
Apple today announced an upcoming product launch that will take place on Tuesday, October 13. We are expecting Apple's announcement to focus on new smart home products, including the long-rumored smart home hub, a new Apple TV 4K, and a refreshed HomePod mini. Subscribe to the MacRumors YouTube channel for more videos. The home hub is an all-new device that's like a cross between an iPad and...
MacBook Pro Ultra Feature 1

Apple to Launch Touchscreen OLED MacBook Pro and OLED iPad mini on October 27

Thursday October 8, 2026 1:31 pm PDT by
Apple will introduce new OLED touchscreen MacBook Pro models and an OLED iPad mini "on or around" Tuesday, October 27, reports Bloomberg. The launch will also include an M6 14-inch MacBook Pro and an M6 iMac. The October 27 follows Apple's October 13 debut of a new smart home hub, a revamped Apple TV 4K, and a refreshed HomePod mini. Earlier this month, MacRumors reported that Apple would do ...

Top Rated Comments

zorinlynx Avatar
92 months ago

This can't be good for the security of these devices...

And have malware installed or spying on you. No thanks. Apple should have gotten their sh** together and not have had the exploit open for nearly a week.
This is a bootrom exploit. It can only be exploited when the device is in DFU recovery mode and will not affect the security of devices being used normally.

This is really the best kind of jailbreak exploit because only the people who really want to go out of their way to jailbreak can use it. Regular users are safe; all it means is that people can do whatever they like with these devices they own now.
Score: 35 Votes (Like | Disagree)
itsmilo Avatar
92 months ago

All the cool kids violate their warranty. Didn't you know?
one restore on iTunes and your warranty is „restored“ so to speak
Score: 29 Votes (Like | Disagree)
tobefirst ⚽️ Avatar
92 months ago
I haaaaaaate the new force press/haptic touch menu on iOS 13. I would consider jail breaking just to go back to how that worked on my X on iOS 12.
Score: 16 Votes (Like | Disagree)
Jeremy1026 Avatar
92 months ago
I haven't been jailbroken since the 3G, what's the big draw of a jailbreak now a days?
Score: 16 Votes (Like | Disagree)
92 months ago

Is there anything exciting going on in the jailbreaking community anymore? Aside from using Apps you don't pay for, is there a reason to jailbreak anymore?
Yes. I have a dash/console integrated iPad Mini 2 in my 1981 DeLorean. It is connected via lightning cable to a Sony headunit installed in a cubby behind the seat. By using Sony's AppRemote app, I can control all stereo functions from the iPad itself. With the iPad being jailbroken, I can enable even more functionality---for example, I have Activator installed to automatically unlock the iPad when the iPad receives power (in other words, the key gets turned and the iPad gets unlocked). I also have it set to open the AppRemote software immediately after being unlocked. Little tweaks like this are nice to have and can only be obtained for me via jailbreaking.

Attachment Image
Score: 14 Votes (Like | Disagree)
Krevnik Avatar
92 months ago

Once the data is copied off the phone can't you brute force it without fear of being locked out? What's the encryption like?
You can read through the details yourself if you want: https://www.apple.com/business/docs/site/iOS_Security_Guide.pdf

The NAND itself is encrypted with AES 256. The passcode is the weak point, but to generate the AES 256 key from the passcode, you need the passcode and the unique AES 256 key burned into the Secure Enclave on the SOC. The passcode is run through PBKDF2 and then tangled with the AES 256 key in a one-way operation.

So dumping the flash raw means you face AES 256 at full strength, even if you know the passcode, because you also need the AES 256 key from the SOC to be able to recreate the key yourself if you aren't just brute forcing AES.

The fastest way to crack an iPhone is to brute force the passcode and bypass the lockout on attempts if you can. It also gives you the most access to the content.

Individual containers/files can be encrypted with separate keys based on the level of access the OS should have in different states of lock/unlock, on top of the NAND encryption. So if you dump the flash unencrypted, you then also need to crack the containers for things like email and messages which are also AES 256 encryption. All the more reason to focus even more on the passcode and attempt lockout mechanisms.


This is a bootROM exploit. Every iPhone ever manufactured excluding the iPhone XS and 11 series will always be vulnerable to this exploit regardless of any iOS updates. There is no patch.
Apple still manufactures the iPhone 8 and 3rd Gen Air. I wouldn't be surprised if we see manufacturing runs of those that include the patched boot ROM.
Score: 14 Votes (Like | Disagree)
Latest Stories
Apple Stores Will Add Your Name to iPhone Duo's Startup Screen
Apple Stores Will Add Your Name to iPhone Duo's Startup Screen
11 hours ago
SpaceX Inches Closer to Becoming a U.S. Carrier
SpaceX Inches Closer to Becoming a U.S. Carrier
11 hours ago
Apple Potentially Behind 'HomeView' Trademark Filed Alongside 'homeOS' Last Year
Apple Potentially Behind 'HomeView' Trademark Filed Alongside 'homeOS' Last Year
14 hours ago
Mark Your Calendar: Six Important Apple Dates Coming Up This Month
Mark Your Calendar: Six Important Apple Dates Coming Up This Month
14 hours ago
MacRumors Giveaway: Win an Apple Watch Series 12 and a Nylon Band From Southern Straps
MacRumors Giveaway: Win an Apple Watch Series 12 and a Nylon Band From Southern Straps
17 hours ago
First Apple TV 4K Now 'Vintage' Ahead of New Model Coming on Tuesday
First Apple TV 4K Now 'Vintage' Ahead of New Model Coming on Tuesday
18 hours ago
The MacRumors Show: Apple's Smart Home Products Are Coming
The MacRumors Show: Apple's Smart Home Products Are Coming
19 hours ago
Apple Shares Fall After News of iPhone 18 Pro Order Cuts
Apple Shares Fall After News of iPhone 18 Pro Order Cuts
19 hours ago
Leak Details iPhone Features for Apple's LG Home Accessories
Leak Details iPhone Features for Apple's LG Home Accessories
19 hours ago
Prime Day Leftover Deals: AirPods Max 2 for $429, Mac Mini for $779.99, and More
Prime Day Leftover Deals: AirPods Max 2 for $429, Mac Mini for $779.99, and More
20 hours ago
Every M5 MacBook Air Now $200 Off on Amazon
Every M5 MacBook Air Now $200 Off on Amazon
20 hours ago
Mac Shipments Fall, But Apple Still Gains Ground in Shrinking Market
Mac Shipments Fall, But Apple Still Gains Ground in Shrinking Market
21 hours ago
Apple Reportedly Cuts iPhone 18 Pro Orders After Price Hike Dampens Demand
Apple Reportedly Cuts iPhone 18 Pro Orders After Price Hike Dampens Demand
22 hours ago
Apple Signs Hiring and Licensing Deal With AI Podcast Startup Huxe
Apple Signs Hiring and Licensing Deal With AI Podcast Startup Huxe
1 day ago
Apple's October 13 Launch: What's Coming
Apple's October 13 Launch: What's Coming
1 day ago
Anthropic Says Users Can't Be Needlessly Cruel to Claude
Anthropic Says Users Can't Be Needlessly Cruel to Claude
2 days ago
Apple to Launch Touchscreen OLED MacBook Pro and OLED iPad mini on October 27
Apple to Launch Touchscreen OLED MacBook Pro and OLED iPad mini on October 27
2 days ago
Apple Now Pushing iPhone Users Still on iOS 26 to Install iOS 27
Apple Now Pushing iPhone Users Still on iOS 26 to Install iOS 27
2 days ago
Apple Has a New M&A Chief as Ternus Reshuffles Leadership
Apple Has a New M&A Chief as Ternus Reshuffles Leadership
2 days ago
Prepare for Apple's New Home Hub With These HomeKit Accessory Deals
Prepare for Apple's New Home Hub With These HomeKit Accessory Deals
2 days ago
Tim Cook Says He's 'Not Meddling' With Apple's New CEO John Ternus
Tim Cook Says He's 'Not Meddling' With Apple's New CEO John Ternus
2 days ago
Tim Cook Explains Why He Stepped Down as Apple CEO Before iPhone Duo Launch
Tim Cook Explains Why He Stepped Down as Apple CEO Before iPhone Duo Launch
2 days ago
Apple Product Launch Announced for October 13: 'Welcome Home'
Apple Product Launch Announced for October 13: 'Welcome Home'
2 days ago
Amazon Unveils New iPad Rivals With Alexa+ and Google Play
Amazon Unveils New iPad Rivals With Alexa+ and Google Play
2 days ago
Missed Prime Day? You Can Still Score Big on Apple Devices Today
Missed Prime Day? You Can Still Score Big on Apple Devices Today
2 days ago
Apple's Cheapest 16-Inch MacBook Pro Just Got a Massive $563 Discount on Amazon
Apple's Cheapest 16-Inch MacBook Pro Just Got a Massive $563 Discount on Amazon
2 days ago
Apple Still Expected to Announce Three New Products on October 13
Apple Still Expected to Announce Three New Products on October 13
2 days ago
Leaker Jon Prosser Pushes Back as Apple Seeks His YouTube Data
Leaker Jon Prosser Pushes Back as Apple Seeks His YouTube Data
2 days ago
iPhone Air 2 Could Be as Thin as an Unfolded iPhone Duo
iPhone Air 2 Could Be as Thin as an Unfolded iPhone Duo
2 days ago
New iPad Mini Rumored to Have 60Hz OLED Display Ahead of Launch
New iPad Mini Rumored to Have 60Hz OLED Display Ahead of Launch
1 day ago