ruckus states that 8090m had a defect and pulled the images. the defect only affected the l2 image which we do not use, but we'll update it to the fixed 8090mc anyway
first flash known uboot, reset, *then* flash the 8090m image. this avoids the errors some users were seeing when their switch came with 8030 era bootloaders that couldn't flash 8090
I have seen on a few switches (4 so far) that they come with the secondary flash as default boot. Even after doing factory set-default it will still boot the secondary flash after updating from the bootloader. The switch models I've experienced this on were the ICX7150 and ICX7250. Since the guide flashes the primary we can just guide people to boot the primary so there is no confusion in case it boots from secondary.