Add notes about flux bootstrap and feature parity

Signed-off-by: Hidde Beydals <hello@hidde.co>

docs/guides/flux-v1-migration.md

@@ -6,7 +6,16 @@ Read the [FAQ](../faq/index.md) to find out what differences are between v1 and
 !!! info "Automated image updates"
     The image automation feature is under development in Flux v2.
     Please consult the [roadmap](../roadmap/index.md) for more details.
-    
+
+!!! info "Feature parity"
+    "Feature parity" does not mean Flux v2 works exactly the same as v1 (or is
+    backward-compatible); it means you can accomplish the same results, while
+    accounting for the fact that it's a system with a substantially different
+    design.
+    This may at times mean that you have to make adjustments to the way your
+    current cluster configuration is structured. If you are in this situation
+    and need help, please refer to the [support page](https://fluxcd.io/support/).
+
 ## Prerequisites
 
 You will need a Kubernetes cluster version **1.16** or newer
@@ -53,6 +62,13 @@ to define the state of your fleet of Kubernetes clusters.
 
 For a detailed walk-through of the bootstrap procedure please see the [installation guide](installation.md).
 
+!!! warning "`flux bootstrap` target"
+    `flux bootstrap` should not be run against a Git branch or path
+    that is already being synchronized by Flux v1, as this will make
+    them fight over the resources. Instead, bootstrap to a **new Git
+    repository, branch or path**, and continue with moving the
+    manifests.
+
 After you've installed Flux v2 on your cluster using bootstrap,
 you can delete the Flux v1 from your clusters and move the manifests from the
 Flux v1 repository to the bootstrap one.