Report client "unbootstrap" or factory reset reason to the server about oma_lwm2m_for_developers HOT 3 OPEN

I understand you want a way for a LWM2M server to know if a LWM2M client did a Reset Factory.

Here I suppose that a Reset Factory will lead to :

• (probably but not mandatory) a client De-register. Note that some client could not implement De-register : "The LwM2M Client SHOULD (not MUST) support the "De-register" operation".
• (probably) a client Reboot.
• (obligatory) a client new Registration.

Using only Core Device Object (Id:3) :

Maybe it's possible for a server to read resource /3/0/3 Firmware version at each new registration and maybe guess if device was reset ?

Using Device Extension Object (Id:3410):

In this object there is some resource which could maybe be used :

like for option above ☝️, maybe you can read the resource at each new registration ?

Using Reboot Status Object (Id:10371):

Some time ago, I register an object which contains :

Maybe a server could observe Reset Factory State ? Or a client use send Operation about Reset Factory State ? (with value resetting before to start the Reset Factory)

Ideally those resource should haven added to Device Object : OpenMobileAlliance/lwm2m-registry#504

If you want to adapt this object (adding Factory Reset Reason ?), we can adapt it and push a new version in LWM2M Registry but this could take time.

About observing the resource :

My personal understanding is that observation is tied to only 1 registration.
That means if the "reset factory" lead to a new registration, observation done before the reset will not be usable after the new registration. (See related issue at : #572)

@mlasch, let me know if this helps and which process you plan to use.

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I understand you want a way for a LWM2M server to know if a LWM2M client did a Reset Factory.

Yes, for example, when a reset button on the device was pressed.

Maybe it's possible for a server to read resource /3/0/3 Firmware version at each new registration and maybe guess if device was reset ?

It is not guaranteed that the version or any other device property changes. In some cases just the configuration is wiped.

Maybe a server could observe Reset Factory State ? Or a client use send Operation about Reset Factory State ? (with value resetting before to start the Reset Factory)

I think this is the way to go and I agree the Reset Factory State would fit very well into the Device Object to report the result of executing 3/0/5 Factory Reset. Too bad the Reset Factory State resource didn't make it into the Device Object for future LwM2M versions. However we can also survive with an additional object like Reboot Status Object (Id:10371).

My personal understanding is that observation is tied to only 1 registration.
That means if the "reset factory" lead to a new registration, observation done before the reset will not be usable after the new registration.

Not sure I understand you correctly, but in my opinion the client should report the state before doing a deregistration and reboot, kind of sending a "last will". In case of a "factory reset", the client might end up in bootstrap mode without any relation to the old server.

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Too bad the Reset Factory State resource didn't make it into the Device Object for future LwM2M versions.

👍
I hope that OMA authors will look at this.

Not sure I understand you correctly

I just wanted to clarify that as I understand the specification, an observe relation can not survive to a de-register/register.

in my opinion the client should report the state before doing a deregistration and reboot, kind of sending a "last will".

Yep an probably that "last will", should be in a "confirmable" way so client is sure that server get the information.

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