Saw your discussion with customer. Replied here.
Checked with L4.1.15.
In normal rootfs, reboot is /sbin/halt.sysvinit.
In initramfs, reboot is linked to /bin/busybox.nosuid
/bin/busybox.nosuid is not the real function of reboot.
//normal rootfs
root@imx6slevk:~# /bin/busybox.nosuid
BusyBox v1.24.1 (2016-09-08 18:25:03 CDT) multi-call binary.
BusyBox is copyrighted by many authors between 1998-2015.
Licensed under GPLv2. See source distribution for detailed
root@imx6slevk:~# whereis reboot
reboot: /sbin/reboot /sbin/reboot.sysvinit
root@imx6slevk:~# ls -l /sbin/reboot.sysvinit
lrwxrwxrwx 1 root root 13 Sep 16 22:35 /sbin/reboot.sysvinit -> halt.sysvinit
//initramfs
UTP: sending Success to kernel for command $ whereis reboot.
utp_poll: pass returned.
UTP: received command '$ ls -l /sbin/reboot'
UTP: executing "ls -l /sbin/reboot"
lrwxrwxrwx 1 root root 19 May 10 2017 /sbin/reboot -> /bin/busybox.nosuid
UTP: sending Success to kernel for command $ ls -l /sbin/reboot.
utp_poll: pass returned.
UTP: received command '$ ls -l /bin/busybox.nosuid'
UTP: executing "ls -l /bin/busybox.nosuid"
-rwxr-xr-x 1 root root 548048 Apr 13 2017 /bin/busybox.nosuid
UTP: sending Success to kernel for command $ ls -l /bin/busybox.nosuid.
utp_poll: pass returned.
