Need help on userinit script. topic

I want a script that will rename a /system/app on boot in userinit (.d or.sh) in /data/local. This is my first script and was thrilled when I was able to get it to work in SManager. I copied the script to /data/local and renamed to userinit.d. Rebooted, checked the file, not renamed. More research, tried various ways, which also work in SManager, but not as a userinit script. I have included the three ways I have tried with attempt counts and used # on two of them. I didn't use these all at once but included them so you could see what I've tried including a delay o allow time for the "mount" to work. This doesn't work in SManager in boot mode. And returns that it cannot rename because it is ro.

Code:

---

#!/system/bin/sh
#
#Renames DSPManager.apk to DSPManager.apk.bak
#export PATH=${PATH};/system/bin;/system/xbin
FN=/system/app/DSPManager.apk
if (FN.exists())
then
# attempt one
#busybox mount -o remount,ro -t ext4 /dev/block/mmcblk0p5 /system
# attempt two
#busybox mount -o remount,rw / 2>/dev/null
#busybox mount -o remount,rw rootfs 2>/dev/null
#busybox mount -o remount,rw /system 2>/dev/null
# attempt three
busybox mount -o remount,rw /system
#thread.wait(3000)
 mv $FN $FN.bak
busybox mount -o remount,ro /system
#thread.wait(3000)
#
#busybox mount -o remount,ro -t ext4 /dev/block/mmcblk0p5 /system
#
#busybox mount -o remount,ro / 2>/dev/null
#busybox mount -o remount,ro rootfs 2>/dev/null
#busybox mount -o remount,ro /system 2>/dev/null
fi

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