So after an unsuccessful attempt I boot from sd card.
Flashing to nand goes ok and it gives the successful message to change jumpers and reboot, but it wont boot, just keeps rebooting.
Any helps would be much appreciated
Then try with the
"official" method which involves flashing to the T9+ firmware (that's Bitmain "quality" support) and then enter the ui of that to "upgrade" to the actual S9 firmware of theirs (2017 or 2018 should work).
If that also doesn't cure it, you might have a damaged nand, and you will be forced to either replace the controller, or permanently use an sd card with bOS in it.
BTW Just looking at the feeds page i spotted a newer experimental bOSminer version... There are no release notes of this 14th September "bosminer preview" release and i don't know if people should upgrade to it, perhaps waiting for release details would be prudent. bOSminer is probably not feature complete at this point, they were saying by the beginning of next year it would be ready...
bosminer is a cgminer replacement written in rust language.