Entware en LE armv5 (RPi 1, con LE 7.0.3)

Comenzamos

mkdir -p /storage/opt
mount -o bind /storage/opt /opt
wget -O - http://bin.entware.net/armv5sf-k3.2/installer/generic.sh | sh
export PATH=$PATH:/opt/bin:/opt/sbin
opkg update
# expr is used in opkg init scripts and is not available in busybox provided by LibreELEC
opkg install coreutils-expr

Creamos mount

nano -w /storage/.config/system.d/opt.mount

Copia el texto

[Unit]
DefaultDependencies=no
Conflicts=umount.target
Before=local-fs.target umount.target

[Mount]
What=/storage/opt
Where=/opt
Type=none
Options=bind

[Install]
WantedBy=local-fs.target

Ctrl O,ENTER,CTRL X

Lanzamos el montaje

systemctl enable opt.mount

Creamos el montaje fijo

nano /storage/.profile

Copiar el texto

export LC_ALL=en_US.UTF-8
export LANG=en_US.UTF-8
export LANG=en_US.UTF-8
export PATH=$PATH:/opt/bin:/opt/sbin

Reiniciamos

reboot

Gracias a @deejayClown por la información