Debian installation on new hardware can be a hassle when it depends on non-free firmware support. A typical workaround is to use a Debian install image which includes non-free drivers, which is available here: Unofficial non-free images including firmware packages. Choose the right image for the kind of USB media you wish to create.
For this post, I chose (amd64 Jessie 8.4.0 netinst + non-free):
$ wget http://cdimage.debian.org/cdimage/unofficial/non-free/cd-including-firmware/8.4.0/amd64/iso-cd/firmware-8.4.0-amd64-netinst.iso
Find a USB stick (which you do not mind formatting entirely; all existing contents will be wiped out with this method), connect it to a working Linux box, and find the device pointer to the stick:
$ sudo fdisk -l ... (other devices) ... Disk /dev/sde: 14.9 GiB, 16008609792 bytes, 31266816 sectors Units: sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disklabel type: dos Disk identifier: 0x156252ec Device Boot Start End Sectors Size Id Type /dev/sde1 * 0 7800959 7800960 3.7G 0 Empty /dev/sde2 20368 21199 832 416K ef EFI (FAT-12/16/32) ... (other devices) ...
We see that the USB stick is attached at /dev/sde in this case (IMPORTANT: this will certainly be different for you; really do make sure the device is the USB stick you would not mind being wiped out).
Then create a bootable installation stick:
$ sudo dd if=firmware-8.4.0-amd64-netinst.iso of=/dev/sde bs=4M $ sudo sync
There appears to be issue writing to USB from isohybrid .iso image, from which I have not been able to create a proper bootable image. Check on this and update the post.