The developer @Chronic has asked a few days ago on Twitter if people would be interested in a fully stable jailbreak based on checkm8 bootrom exploit for all the supported devices (iPhone 4S all the way up to iPhone X), on all supported iOS versions (iOS 6 to iOS 13.x). Obviously, he has a big support by his follows asking him to make a tool to jailbreak like years before. It’s only been a couple of days since developer @axi0mX made history by releasing the very first iOS BootROM exploit in nearly 10 years from the last iphone 4 BootROM , and tools that make use of it already start coming into the internet. Of course, Apple knew about the vulnerability and newer devices such as 2018’s iPhone XS iPhone XR and iPhone XS Max have the bug patched. Jailbreak it will be the key to make a custom firmware.
A CFW does not bypass SEP. At best you can create a CFW (using a signed SEP) that looks like the iOS you want.
How about custom firmware (cfw) on iOS to bypass icloud?
One of the best methods to bypass icloud is a Setup.App Patch like on iPhones 32-Bit using iOS 7.x.
The Setup.App if removed from signed firmware will jump directly to iOS springboard. it will not activate your device, but all functions will open and some will work normally others not. Carrier signal, facetime, SMS, are some of the functions that do not work without icloud activation.
If you use checkm8 with A5 / A6 devices, you can easily restore with CFW. These technologies are already established. I could have a simple script ready for untethered iOS 7 iBoot exploit (untethered downgrade) and a tethered downgrade that doesn’t require an iOS 7 blob.
Tethered method ( CFW WITHOUT SETUP.APP )
A5 / A6 devices -> DFU -> checkm8 -> Run PwnedDFU -> restore CFW -> stock Recovery Mode -> Re-Enter DFU -> checkm8 -> PwnedDFU -> JustBoot