Ok, i've got a redboot on a bunch of nanostations, but this does not help with my existing nanostations on the roof.
Usually, i brick my nanos with experimental firmware images and have to climb ....
So i want a tftp-boot_wait redbook on my roof without climbing up there. I have to flash it from my livingroom.
step1: brick my dir-300
Before flashing my redboot from inside openwrt on my nano, i prefer to test with cheap hardware, in this case a dir-300 from d-link, which is a pain in the ass anyway, as i need the terrible dir300flash util or telnet into redboot. A little bit of research showed up, that the redboot on openwrt is NOT writeprotected by the kernel. So after copying dir300.rom to /tmp of my dir, a simple
mtd write /tmp/dir300.rom RedBoot
wrote the image into the bootblock. After a reboot, the dir was waiting for tftp on 192.168.1.1.
The next step was the nanostation, in this case i used ubnt_ns2.rom and did everything like before.
It worked and now i got a new firmware on my rooftop-nano and will hopefully never go up there for a firmware update.