The correct method to restore the CFW syscalls are:
1. Disable the syscalls using the preferred method (R2+△)
2. Go to the CFW Tools and press "Create Syscalls" option
3. Done.
I am getting the "Cobra must be 8.3 or higher" error.
or
1. Press "Allow Restore Syscalls" in the CFW Tools to enable the feature. (This is needed only once)
2. Disable the syscalls using the preferred method (R2+△)
3. Go to the System Update menu in the settings and exit of the update screen without do anything
4. Done.
Yes, it is needed to press only once. But I have to press "Create Syscalls" option additionally to avoid a hard freeze of the console after launching a homebrew app.