diff --git a/README.md b/README.md
index f458e9a7..75b362a9 100644
--- a/README.md
+++ b/README.md
@@ -141,6 +141,17 @@ nix run .#microvm-update-spaceapi
 nix run .#microvm-update-spaceapi-local
 ```
 
+### Update MicroVM from our Hydra
+
+Our Hydra runs `nix flake update` daily in the `updater.timer`,
+pushing it to the `flake-update` branch so that it can build fresh
+systems. This branch is setup as the source flake in all the MicroVMs,
+so the following is all that is needed on a MicroVM-hosting server:
+
+```shell
+microvm -Ru $hostname
+```
+
 # Secrets management
 
 ## Secrets managment with PGP