The Arm architecture provides a set of guidelines that any software should abide by when accessing the memory with MMU off and update page-tables. Failing to do so may result in getting TLB conflicts or breaking coherency. In a previous talk ("Keeping coherency on Arm"), we focused on updating safely the stage-2 (aka P2M) page-tables. This talk will focus on the boot code and Xen memory management. During this session, we will introduce some of the guidelines and when they should be used. We will also discuss how Xen boot sequence needs to be reworked to avoid breaking the guidelines.