How do I install this on USB ?

[funderscore1]

I don't know how to install this on USB (with the boot file in sd).
Can somebody help me ? :)

[tesses50]

This worked for me, I don't know if this will help (your pc will need linux, even using a live environment (not installing it to your pc) will work Ubuntu desktop version)
if your pc has linux or you have a linux box you can skip this step for downloading ubuntu

first of all use gparted to delete all partitions from usb drive then create ext3 partition
download this file somewhere (I copy it to the root of the drive after downloading) rootfs.tar.xz

at the root of the usb run this command:
tar -xvf rootfs.tar.xz
you can optionally run rm rootfs.tar.xz to delete file

on your sd card (required also)
this should be formated as fat32 if not already
download bootmii.tar.gz
to sd card and use
tar -xvf bootmii.tar.gz
you can optionally run rm bootmii.tar.gz to delete file

fyi the usb can be a Hard drive also (That what I use, mine was internal with sata to usb converter)

hince you need to change the zImage file (this step is only If you dont have an existing sd based install)
download this file baedit

sudo apt install golang-go
CGO_ENABLED=0 GOOS=linux go build -a -ldflags '-s -w -extldflags "-static"' baedit.go

replace SDROOT with the media path of your sdcard
replace /dev/sda1 with /dev/sda if your ext3 partition is not the first partition on the usb
./baedit SDROOT/gumboot/zImage.ngx 'root=/dev/sda1 console=tty0 console=ttyUSB0,115200 force_keyboard_port=4 video=gcnfb:tv=auto loader=mini nobats rootwait'