Re: the Black screen issue - If you are using the Linux Game Console, and if you did not specify an app/game to run with the START= parameter or via SSH, the black screen is an expected behavior.
This AMI is configure to be launched without a desktop manager, you could test by connecting to the instance with the following URL (replace instance IP/GUID):http://aws.otoy.com/?connect=//xxx.xxx. ... CK=0;GUID=
Re GUID issue:
In order to specify your own GUID within the User Data under the EC2 console, the instance must be in a stopped state. Once the instance is stopped, you could then select the instance you wish to edit by right clicking on the highlighted instance and select View/Change User Data, then simply fill in the predefined GUID: GUID=xxxxxxxxx
Where the <guid> field is replaced by a randomly generated GUID token. If you require other data to be present in your userdata field, then the GUID field should come first, and must be separated from any other data by an ampersand (&) character, a semicolon (;) character or a newline character.
Note that case is important, and any letters should be the same case as they are supplied to the host.
Note also that if a user supplied token is present, then it overrides the automatic generated token.
Once the above steps have been completed, you could then restart the instance and reconnect with the predefined GUID in your connection URL.
Please PM me if you have any further issues with the service and I'll be happy to assists you.