ice40-stub has slightly broken instructions because prerequisites are both depreciated

I had luck with riscv-none-elf though, which replaced it. Work-around(s) follows:

Used XPM to install https://github.com/xpack-dev-tools/riscv-none-elf-gcc-xpack (following current instructions there), into a fake project at /opt/xPacks/, I.E.

cd /opt
mkdir xPacks
cd !$
xpm init
xpm install @xpack-dev-tools/riscv-none-elf-gcc@latest
cd

Then put

export PATH="/opt/xPacks/xpacks/.bin:$PATH" # for riscv-none-elf-*

on the end of my .bashrc

also: YosysHQ/fpga-toolchain is depreciated for YosysHQ/oss-cad-suite-build and/or YoWASP if you really want static binaries (which are very portable). I went with oss-cad-suite-build nightly release tar xf'd into /opt, and also added (again, to .bashrc):

export PATH="/opt/oss-cad-suite/bin:$PATH"

Finally, I could build successfully with:

cd
. .bashrc
cd no2bootloader/gateware/ice40-stub
CROSS=riscv-none-elf- make bootloader

Hope this helps

no2fpga / no2bootloader