Can someone explain the relationship between ONIE and some installed Networking OS, like DNOS9/FTOS in a simple way?
First, when I was reading about upgrading ONIE, I saw that when upgrading they need you to have a minimum previous version of ONIE (obviously), and it also seems linked to BIOS and CPLD.
Now, when looking requirements for upgrading the Networking OS, in this case DNOS, they have a requirement on the minimum ONIE version (so far, so good), however: The DNOS image seems to contain images for 1) boot-flash 2) boot-selector 3) CPLD. Now both ONIE and DNOS are somehow linked to the CPLD for example.
So my questions:
1) In case I would like to upgrade all parts of the system to the most recent releases, what would be the correct order to upgrade in order to fulfill all dependencies at all times?
2) What is in fact the actual order of the parts of the system booting? BIOS -> Boot-Selector (Grub) -> Boot-Flash (???) -> ONIE -> NOS? (What exactly is the Boot-Flash etc. anyway?)
This is especially strange as for example DNOS seems to be installed just like ONIE (you can select it in the boot loader). So if only one can be selected, where is the part where they depend on one another?