Update Build and Deploy HoloLens Guidance Doc

[CDiaz-MS]

Overview

Selecting ARM as the build architecture in Unity 2019.3.x results in a fails to deploy to a HoloLens device. A note has been added to the Build and Deploy doc for HL and HL2 devices to use ARM64 instead of ARM for Unity 2019.

Changes

• Fixes: Cannot deploy to HoloLens 2 device - Unity 2019.3 #7858

[julenka]

There are some plugins that people use, for example some plugins in projects I'm working on, which do not compile for ARM64. What is the root reason why MRTK 2.4 does not deploy for HoloLens 2 in ARM? MRTK 2.3 deploys ARM in Unity 2019.3 just fine. Seems like not supporting this can break customers.

[keveleigh]

@julenka

What is the root reason why MRTK 2.4 does not deploy for HoloLens 2 in ARM? MRTK 2.3 deploys ARM in Unity 2019.3 just fine. Seems like not supporting this can break customers.

The root cause and how to work around it is in this doc / guidance. It's not an MRTK issue, but a Unity one:

If the ARM architecture is required, navigate to Edit > Project Settings, Player, under the Other Settings menu disable Graphics Jobs. Disabling Graphics Jobs will allow the app to deploy using the ARM build architecture for Unity 2019.3.x, but ARM64 is reccomended.

[julenka]

Ah, got it thanks @keveleigh !

[keveleigh]

@julenka I also suggested some changes to help make it more clear and add the Unity bug tracker!

[david-c-kline]

/azp run mrtk_docs

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