In fact, fusing KNOX warranty is just like unlocking Bootloader. Modifying the system kernel at the expense of destroying the system security system will lead to the lack of the security system necessary for running high-security applications, such as the seamless mode of SAMSUNG PAY or Samsung browser.
However, the root privilege is too powerful. Like xposed, it can directly modify the running command of the application at the command line level with active memory without modifying the advanced permissions of the application ontology, and it is often abused by selfish functions such as "automatically grabbing red envelopes" and "permanently saving flash photos", and even "automatically activating device manager" to force users to encrypt and blackmail, which is why Android 6.0 began to crack down on root permissions.
The conventional root permission activation mode needs to modify the boot partition and the system partition (even the data partition) at the same time, but the system partition is locked by sepolicy and cannot be modified, which will lead to incomplete permission activation and boot failure (usually the first logo you see after booting).
The current root rights manager is basically helpless for the sepolicy that started with Android 6.0. However, some managers (such as SuperSU of chainfire) have developed a system-less firmware writing mode (such as SuperSU's System less mode) to "root privilege simulation" by only modifying the boot partition and data partition (simulation is because the system cannot be completely modified), and sometimes there are strange situations such as "root can still run OTA updates, and SuperSU will be reinstalled after OTA updates are completed". But xposed is to modify the active memory command line, that is, to write firmware in the system partition. The "root privilege" that xposed originally relied on could not be written into the system, and the installation of xposed failed as expected. (So does the busybox toolbox.)
Even so, don't "do everything possible" to brush in xposed through recovery. The reasons are all mentioned above. If you write an incomplete system installation, it will not start.
(Last time, I failed to boot because I directly used recovery to brush xposed. I conducted the "Samsung Brick Saving Plan" for five days and four nights. Therefore, all applications, including user applications and system settings, are fully initialized. )
(Appendix)
If the Android version of your Samsung mobile phone is above Android 6.0, you can only activate the root permission through "no system", and the chain fire pipe network has an Odin line brush version suitable for Samsung. After downloading the brush through Odin, it will replace the recovery firmware and specify the forced systemless installation mode of SuperSU card brush program. After swiping the card, the system needs to rearrange the bootloader (don't think that the logo screen will crash after it is repaired, the Boot and the system will be changed long ago when the boot animdataion appears, and the application time will be 20 minutes at most, and it will automatically restart after completion). The activated root permission can only modify the user's installation application (the lucky cracker can also save it).
In the future, Samsung mobile phones will not only be recycled with Odin. Odin is Samsung's exclusive advanced line brush tool, which only guarantees the perfection of Samsung mobile phone brush.