A Reddit user has been able to successfully install and run Ubuntu on his iPhone 7, without jailbreaking it. He was able to boot the gull desktop user interface for Ubuntu, along with working Internet connectivity.
The iPhone 7 in question had a dead NAND, which meant that it was unable to boot iOS. Using a combination of iPhone’s recovery mode, checkra1n, PongoOS, and a Linux fort for A10, he was able to install Ubuntu on the smartphone.
Here is Ubuntu 20.04 on an iPhone 7
User hacker1746 posted the details on Reddit of how he was able to accomplish this and even shared a step-by-step guide. It is not the simplest process and only works with iPhone 7. Unless you know what you are doing, we don’t recommend that you experiment on a working iPhone 7.
Here is a video of Ubuntu 20.04 booting on iPhone 7. Now the next step should be running DOOM on Ubuntu on iPhone 7.
Regarding the jailbroken iPhone bit, the user clarified that he has never jailbroken his iPhone before. As the iPhone 7 NVMe NANAD is inaccessible, he is not even able to boot iOS on the smartphone. He credits Linux kernel port for A10 which allowed him to install Ubuntu without jailbreak his iPhone 7, however, he had to use checkra1n for bootrom exploit and the ability to run unsigned code.
It’s been reported that I am running on a “jailbroken” iPhone and that to be able to do this one has to have already jailbroken the phone. That’s not correct; in fact there’s no possible way for me to jailbreak this iPhone, as its NVMe NAND is downright inaccessible. That is to say, iOS will never be able to boot on this phone. If there weren’t a Linux kernel port for A10, one might be able to affectionately call this phone not a Linux phone but a brick. One can pull all of this off without ever jailbreaking the phone. The only reason I’m using checkra1n is for the bootrom exploit and unsigned code execution. In fact, this iPhone had never been jailbroken before flash failure. I got it from my grandma who had the NAND die on her suddenly.
This is not the first time that a non-iOS operating system has been installed on an iPhone. postmarketOS, a Linux distro specifically for smartphones, is also available for iPhone 7 and iPhone 7 Plus, and can be installed using checkra1n and PongoOS. You can check out the detailed process here. It works with Bluetooth and Wifi enabled, but don’t expect a polished experience like iOS.