Hope this helps. If I mention a tool that you don't have l, just Google it and download it.
We will be using DS3617xs as it offers a bit more IMO. If you want to use a different model just substitute the extra drivers file, the serial number generator, DSM and loader files.
1. Download the loader https://mega.nz/#!zcogjaDT!qIEazI49daggE2odvSwazn3VqBc\_wv0zAvab6m6kHbA
2. Download the extra drivers http://s000.tinyupload.com/?file\_id=06641076704622277403
3. Download DSM https://archive.synology.com/download/DSM/release/6.2.2/24922/DSM\_DS3617xs\_24922.pat
4. Use a new flash drive or clear a flash drive using diskpart in CMD. I recommend a USB 2.0. and go into the device properties to get the vid and pid records.
5. Mount the loader you downloaded in step one on OSFMount. Select partitions 0 and 1 in step 2 by pressing ctrl button while clicking. Make sure read only drive is unchecked in the next step. 2 drives will pop up.
6. Get a serial for your deployment from here https://xpenogen.github.io/serial\_generator/index.html
Make sure you choose the model DS3617xs
7. Edit the grub/grub.cfg file. It is located in the first drive.
Changing the following
!!!! are vid and pid. a set of 4 numbers.
@ is the serial you generated in step 6.
$ is your network nics addresses without the ':'. I have 4 nics so there are 4 records add or remove records as necessary.
Change the following record to have 4 instead of 1
save the file and close.
8. Open the extra drivers downloaded in step 4 with 7zip and put the file extra.lzma in the second drive that was mounted in step 5.
9. Open the DSM downloaded in step 3 with 7zip and take the files rd.gz and zImage and put them next to extra.lzma we copied in the previous step.
10. Dismount all drives and exit OSFMount.
11. Run Win32DiskImager and flash the loader we mounted and edited with OSFMount.
12. Put it in the USB slot of your server. Preferably the USB on the motherboard if you have one.
13. Boot your machine and go to BIOS settings. change boot type to BIOS and make the USB with the loader on it the first thing to boot and reboot the machine.
14. download Synology Assistant https://global.download.synology.com/download/Tools/Assistant/6.2-24922/Windows/synology-assistant-6.2-24922.exe
15. wait for the message 'Happy Hacking' and launch Synology Assistant and hit search till you see your machine come live. It will take around a minute to 2 minutes.
16. When going through the installation of DSM. Do a manual install and upload the file downloaded in step 3.