I have Kali linux setup on a 32GB SD card that is plugged into my laptop, at the point of the install where it asks where would the bootloader gets installed doesn't actually install grub to my USB flash drive.

A bit of info about the laptop, it's an Acer Aspire V Nitro VN7-792G-79LX that has a SSD and a 1TB storage drive. What I'm wanting to do is keep my SSD and my storage drive untouched and run Kali off of my SD card. However my laptop doesn't support booting from SD, leaving me to boot from USB, I have a 2GB USB flash drive I wouldnt mind putting GRUB onto and being able to use that to load Kali from my SD card. However though in the installer it fails to actually install GRUB to the USB device (no errors or anything) but the USB device remains untouched.

Is it even possible to install GRUB onto the USB flash drive to load Kali from the SD card? If so how would I go about accomplishing this?