Just got 3 x RB1200 to install.
was trying to downgrade to 4.17.
was monitoring process on serial after 2 of them crashed.
downgrade is going fine but after reboot I can see only " Kernel not found " message.
Had to reinstall with net install.
as well was trying to netinstall 4.17 and resoult was the same.
Any Ideas?

RB1200 is v5.x only board. It was developed after v4.17 - so it doesn't work.

exactly , RB1200 will not run with RouterOS 4.x or older.

You should have got RB1100(AH). Runs fine with 4.17.

for better experience, if board comes with software version X.Y then do not downgrade to anything lower than that. when release X.Y-1 could still work, mayor release down X-1.Z will not work

I made the mistake of downgrading to version 4 as well. Then had to use netinstall to get v5 back on there!

Good to hear that. will give me chance to get closer to 5.xx ver
1 more XP point.

In my case too install him the version 4.17 to my RB 1200, already did the process with Netinstall for reinstall the version 5.11, I format the Nand but the system on hyperterminal show me a ethernet link error, can you help me please?

sorry for my english

You should have got RB1100(AH). Runs fine with 4.17.

probably only the old ones. new revision has different CPU and needs v5