Mikrotik hap ac 2 | Unable to downgrade

So, I was trying to downgrade my new mikrotik hap ac 2, to install Openwrt of course. I get a log message after I click on downgrade reboot:

omitting package routeros-arm-6.45.8: min RouterOS version is 6.45.9

Is this a new trickery by Mikrotik? Am I missing something?
My router came installed with 6.48. something
This is my router info:

Model RBD52G-5HacD2HnD
Revision r3
Serial Number HC238BEFAD34
Firmware Type ipq4000L

I played around with RouterOs for a while and I am scared of it!

Why do you want to downgrade?

The RouterOS command /system routerboard print will show you "factory-firmware", which you cannot downgrade past from within RouterOS.

I want to install Openwrt on it
This article says: https://openwrt.org/toh/mikrotik/common
I need to be below 6.46

Below RouterBOOT v7 should be fine.

Aaah. Thanks a lot for this info.

However, I think then we should update that article. I wasted my whole day with that sadly.