Not shure if this feature is under consideration ... ?
Would be a big gain being able to terminate a gretap-tunnel to a RB-device.
As far as I understand the protocol-numbers used in the header are different in Linux-gretap and RB-EoIP.
Since newadays a lot of wireless-devices using gretap-bridging to work around Vlan-constraints, it would be an asset to have this feature in RouterOS.
So ... I am proclaim a feature-request:
gretap-compatibility for RouterOS

+1 for gretap. It is much required.