Combine sago, grated potatoes and water in a saucepan.
Add salt, cumin seeds and red chilli flakes.
Cook on high heat for 25 minutes, continuously mixing with a spatula. After 25 minutes, the mixture will thicken and starch from sago will start forming a thin layer along the edge of the pan.
Remove from heat and let it cool and become warm.
Ladle out portions of this mixture and spread it evenly on a silicon/plastic sheet under the sun.
Sundry till the papads lose their moisture and nothing sticks to your fingers when you touch their surface. Then peel them from the sheet and invert them.
Let them dry till they become brittle. Then collect them.
Store in an airtight container till further use.
When you want to consume them, take out a few, as per your requirement, and deep fry them in medium-hot oil.