I had a simular problem with a san disk 128 gb ssd but during a fresh install of debian 9 on a dell E6230 laptop. Before the install the ssd was wiped totally and overwritten several times including mbr. This leads me to the conclusion that there is something hindering grub, maybe on a controller chip and not on the harddisk area, and this can only be unlockled from a recent (win 8 or 10) installation. After installing win 10 you will need to shrink the partition for dual boot. You will also need to disable various utilities relating to the boot process. You will need to enter a one time boot menu with the debian installer usb in legacy mode (not uefi). If you are extremely lucky you may have succees. see https://www.lifewire.com/dual-boot-windows-8-1-debian-jessie-2202088
in the language of the author it was a bizarre process, but it works. Regards
