update: I have tried with a “Transcend 256GB PCIe™ Gen3 x4 M.2 SSD 2280” and with a " KIOXIA EXCERIA NVMe 500GB PCIe 3.0 Gen3x4 M.2 2280 SSD", both not working.
I have tried both the nvme and mmc June 2023 Debian images, setting the boot switches on the board accordingly (to the image selected).
Both are kind-of mentioned in the thread What kind of SSD can be used?, although it could be that the models are slightly different. For the Gentoo test, IIUC the person who tried it didn’t boot from it.
Finally, I have used dd as explained above for all tests:
sudo dd if=starfive-jh7110-202306-x-minimal-desktop.img of=/dev/nvme0n1 bs=1M status=progress conv=fsync
do I need to update the SPI flash? If so, how? Is there a document/procedure?
and thank you all for the pointers so far