"message": "Boot volume ocid1.bootvolume.oc1.iad.abuwcljro5zeuegg7i2ms7xoaxgeft5mpef3ucykogfehtjhjde3zy676ddq cannot be attached to instance ocid1.instance.oc1.iad.anuwcljroksebviczqhtrjxzsu2d7angpz3bnpnl5z5gko27spvqlacxvicq. It can only be attached to its parent instance.",
I googled it but could not figure out why. I will look into the issue when I have some time. Now my only option is to create a new instance out of the restored boot volume.
If you navigate to the restored boot volume, you can create a new instance.
Now that I was able to create an instance out of the restored boot volume, I was able to get the text.txt file I created in my home directory. And the second line I created after backing up was not there.
In a sense, this experiment was successful but I still need to figure out why I was not able to attach the restored boot volume to the existing instance.