How to use Microsoft Graph SDK for PowerShell to update a registered Device’s Extension Attribute

Below is a sample PowerShell script showing how to update a registered device’s extension attribute. The sample uses extensionAttriubte3. You can easily swap this out to a different one. Refer to the Update Device documentation for more info.

Import-Module Microsoft.Graph.Identity.DirectoryManagement
# Log in with the correct scope
Connect-MgGraph -Scopes "Directory.AccessAsUser.All"

$DeviceId = "<Device ObjectId>"
$params = @{
   "extensionAttributes" = @{
      "extensionAttribute3" = "hello2"
   }
}
# Update Device
Update-MgDevice  -DeviceId $DeviceId  -BodyParameter ($params | ConvertTo-Json)

<# 
The following technique to create json payload also works.  Thanks to my colleague Will Fiddes for the idea
$json = '{ "extensionAttributes": { "extensionAttribute1": "BYOD-Device" } }'
Update-MgDevice -DeviceId $DeviceId -BodyParameter $json
#>

# Query Device
Get-MgDeviceById -DeviceId $DeviceId

Note: The above device update operation requires the signed in user to be in either the Intune Administrator role or Global Administrator role.