I'm going to link you some threads on the failures, do not listen to the suggestion that it's incompatible drives that are the cause. If the drive were the issue then it would have been an easy solution but all they can do is suggest you spend a bunch of cash on different drives that other people have had success with only to find out that it won't work. There is a flaw in the code on ASUS's side that they aren't admitting to nor resolving.

https://rog.asus.com/forum/showthread.php?51237-ASUS-Backtracker-failed-to-read-from-usb-when-imagin...
https://rog.asus.com/forum/showthread.php?54292-G751JT-CH71-Asus-Backtracker-to-SSD-problem
https://rog.asus.com/forum/showthread.php?53672-Help!-Backtracker-just-bricked-my-G751JT-CH71
https://rog.asus.com/forum/showthread.php?54938-Please-help-Asus-G751JT-backtracker-issues

Ok Backtrack is design to replace a recovery DVD Set. It has in the past worked to restore to a new smaller SSD. As you are seeing here there have been some failure trying to use it to recover to a smaller SSD.
Backtracker is your best way to return your notebook to factory condition.
I have had lots of failure to boot after restoring Acronis Images. I have 5 computer in my network at one time all 5 were on Acronis and all was well until I got this notebook Acronis had been advertising UEFI Compatibility since 2010 late Verision. and 2011 for sure. however their software could not restore a booting OS Hard drive/SSD. As late as 2014 people were still having issues restoring, then with the 2015 version they completely changed there user interface. Spend some time in Acronis Support Forum. They have worse tech support than Asus. Use it at your own risk. I had already changed over my UEFI units to Macrium Reflect since back in 2012 they were the only cloning/Imaging software that could restore a booting UEFI GPT OS Disk/SSD Free edition. I have since paid for the Pro Version and have removed Acronis completely. Macrium Recovery media tool is very easy Win PE. they have a great support forum and tech support that understands how their software works. For merely Cloning a hard drive to a new hard drive or just making disk images all you need is the Free addition. If you want to use MR as back up software backing up files and folders setting up schedules then you need to get the paid for version. MHO

I don't know the correct answer for sure. But ordinarily the recovery partition would be on the same drive as the OS all should be on the M.2 SSD. I'm pretty sure that is the case as for instance if you were to run a F9 recovery we would tell you to remove your other hard drive because if you didn't it would get formatted too. The Recovery partition is copied to the USB stick using Backtracker. restoring either way will put your notebook just as it was shipped including any 2 hard drive you have if you don't remove it before the restore.

i got a recovery partition but it is only 900MB and it is hidden.. you need to use "diskpart" to access it. i can see all the files there but unable to use those file, cant even use the default windows "create backup recovery"...
can anyone tell me how can i create a recovery USB drive.. without the use of backtracker...
for now.. what i do for now is copy all the files on the recovery partition, and make it bootable (havnt tested yet)..
pls help.. run into trouble BSOD error: 0x0000001

Asus recovery partition is more like 12 Gb not sure but windows alone is 4 GB plus all the required drivers and bloat ware. Use 'MiniTool partition Wizard you can see all your partitions including hidden ones

on my G751 JY with EaseUS Partition Master 10.5 i see a recovery partition with 12 Gb, in use is about 10,87 Gb.
With this Software i could create a backup harddisk with the C-Partition. You also can copy it on a greater harddisk like you want to do.