Installation doesn't detect my USB flash drive

I’ve been trying to overcome what seems should be a simple problem if the installer weren’t so simple that it doesn’t let you tell it what to do. I’m installing from a 16 GB USB flash drive (prepared with dd from linux) to an 8 GB flash drive (if it matters i’m using the smaller one because it’s much faster and AFAIK only 8 GB are necessary). The problem is, when i get into the install it doesn’t show either USB drive as a potential destination (i wouldn’t necessarily expect it to show the installation media anyway, but i don’t know if that’s normal or not). I verified that both the USB drives are detected devices by checking /dev/sd* and identified that /dev/sde is the 8 GB drive using print devices in parted from the console in the install session.

If there were a way to say “install to /dev/sde whether you think it’s there or not” it would be great, but i can’t find a way to do that.

Things i’ve checked:
both usb drives automount fine when i boot into my debian install on the same box i’m trying to convert to a Rockstor NAS.
i’ve twiddled all the USB-related BIOS options
i’ve deleted the existing partition and repartitioned the target drive FAT32 using gparted
I’m not sure it would help but i think i may have banged my head against it, too.

I’m not familiar with the rpm side of the divide so maybe i’ve missed an install parameter i could use. If not is there an alternative way to install, sort of a live disk setup? I’m really excited for a btrfs/linux NAS but i’m not sure what else to try here. Thanks.

ETA: I’ve discovered if i unplug and reconnect the 8GB drive after entering Install, it will show up (sometimes) as an install drive option, but then the install program will crash. It almost seems like the program will only recognize one USB drive at a time, so doing that makes it lose track of the install media.