Cannot boot into android x86, grub doesn't appear

[EkosFox]

Hi guys, could you help me? I tried to install android 7.1 RC1 86x firstly for BIOS(legacy) mode because i like to keep the second OS hidden then I can boot directly to Windows 8.1 on EFI, then I selected to install grub but after I restart the PC my stock bootloader was still starting saying that doesn't have a bootable device and nothing of grub and therefore I cannot boot into android. Then I decided to install for EFI because I was a whole day trying to work that out and couldn't find any answer on Internet, however seems like the stock bootloader starts instead of grub after I restart the pc.
Extra information:
My pc has an E1-2500 AMD processor, it is 64 bits (and yes, i downloaded the right iso file).
Windows boots from EFI, and I had Kali Linux previously installed with grub and worked fine.After I removed kali I also removed grub with "bootrec /fixmbr" and "/fixboot" on command prompt.
Windows is working fine.