As in ROS 4.4 there is no /system>routerboard>settings command, is there any other way to put the board in etherboot mode from CLI/winbox ?
RB devices traditionally have a mode button which in certain event train causes device to enter netinstall mode.
Beware that upgrading from ancient versions of ROS can sometimes cause loss of license. I suggest you to contact Mikrotik support (e.g. via email support@mikrotik.com) to get advice on how to properly do whatever you’re after.