The problem you have it is caused by the way you use to run your setup "Test1_1_0_1.exe " from "Test1_1_0_0.exe ".
In other words, when you launch the upgrade (once downloaded) from "Test1_1_0_0.exe ", the calling exe is still active while executing the second one. When the second one completes the Net 4.0 runtimes installation, terminates has expected calling Reboot and Resume (the command writes the REG KEY RunOnce).
But your calling installer it is still running and terminates itself after the second one is terminated, then also, you write again to the same REG KEY RunOnce.
So in this way it is very probably that it will fails!!
To solve your problem just change the way you use to execute your "Test1_1_0_1.exe " when called from "Test1_1_0_0.exe".
In your Test1_1_0_0.exe Update Script:
- Download the file and save to a path.
- Run the file and do not wait for program to finish
- Force Terminate Install (do not call reboot, Reboot & Resume and avoid any write to RunOnce)
In this way, once download its completed the "Test1_1_0_1.exe" it is excuted and "Test1_1_0_0.exe" will terminate immediately. After, Test1_1_0_1.exe will complete the install and terminates with Reboot and Resume.
You should solve definitively doing this.