Here starts my trilogy about UEFI & SliTaz
This first tutorial describes how to do an EFI LiveUSB of SliTaz Next from a SliTaz Rolling session.
It doesn't matter that the operating system is 32bit or if your EFI computer is 64bit. The only imperative is a 64bit computer needs a 64bit EFI boot loader to start.

Insert a USB stick; if your file manager is set to mount removable media automatically when they are inserted, unmount the stick but don't eject it.
Open a terminal as the root user and change in /root:

tux@slitaz:~$ su
Password: 
root@slitaz:/home/tux# cd /root
root@slitaz:~# 

Identify the stick:

# fdisk -l

# mkfs.vfat /dev/sdb1

Set the flags boot and lba to your stick:

# parted /dev/sdb set 1 boot on
# parted /dev/sdb set 1 lba on

Don't pay attention to the messages Information: You may need to update /etc/fstab.

Download the SliTaz Next ISO.

# wget http://mirror1.slitaz.org/iso/next/slitaz-next-170930.iso

Here are two possibilities: use tazusb or copy the files manually.

In the terminal, type:

# tazusb gen-iso2usb slitaz-next-170930.iso /dev/sdb1

When tazusb has finished the job, exit and mount the stick:

# exit
# mount /dev/sdb1 /mnt

Go to step 3

Mount the stick:

# exit
# mount /dev/sdb1 /mnt

Mount the ISO file:

# mount -o loop slitaz-next-170930.iso /media/cdrom

Copy the files to the stick:

# cp -r /media/cdrom/boot /mnt

Unmount the ISO:

# umount /media/cdrom

Create a /efi/boot directory on your stick:

# mkdir -p /mnt/efi/boot

We are going to install GRUB 2 but it exists on other boot loaders compatible with EFI.

Install the grub2-efi package:

# tazpkg -gi grub2-efi

Copy the boot loader in the /efi/boot directory you previously created on your stick:

# cp /boot/efi/boot/bootia32.efi /mnt/efi/boot/bootia32.efi

Download the bootx64.efi file from the Next64 project.

wget http://cook.slitaz.org/next64/grub2/browse/taz/grub2-efi-2.02/fs/boot/efi/boot/bootx64.efi

Copy the boot loader in the /efi/boot directory you previously created on your stick:

# cp bootx64.efi /mnt/efi/boot/bootx64.efi

Create a /boot/grub directory on your stick:

# mkdir -p /mnt/boot/grub

With your preferred text editor (ie nano), create a configuration file for GRUB 2:

# nano /mnt/boot/grub/grub.cfg

Example:

### CONFIGURATION FILE FOR GRUB 2 ###
#

# Comment the line if you want SliTaz to start automatically at boot or
# change the value to define the time (seconds) to wait before booting.
set TIMEOUT=-1

# Menu 0: boot SliTaz Next
menuentry "SliTaz Next (ISO 20170930 - kernel 4.9.30)" {
   set root=(hd0,1)
   linux /boot/bzImage ro root=/dev/null video=-32 autologin
   initrd /boot/rootfs.gz
}

   linux /boot/bzImage ro root=/dev/null video=-32 kmap=fr-latin1 autologin

# umount /mnt

Your Live is ready. But maybe the hardest remains to do.

Computers that came with Windows 8 / Windows 10 preinstalled start in Boot mode= UEFI and have the Secure boot= Enabled. The Secure boot prevents the loading of drivers or OS loaders that are not signed with a digital signature ($old by Microsoft).
With SliTaz not having any digital signatures, you have to disable the secure boot. The following lines describe how to do it on a hp Laptop 17-bs032 but it can be different for you; there are almost as many ways as there are manufacturers…
Even access to the Setup is different from one computer to another. If you don't know how to access the setup, have a look here (sorry for french; I couldn't find an equivalent link in english).

On the hp Laptop 17-bs032, press the [F10] key immediately after you've powered on the computer until the BIOS Setup Main page is displayed. Use the right arrow to display the System Configuration page.










Select >Boot Options

Insert your Live in a USB port and restart the computer.

If you didn't modify the UEFI Boot Order, access the Multiboot menu.
If you don't know how to access the Multiboot menu, have a look here).