diff --git a/content/en/docs/next/operations/configuration/platform-package.md b/content/en/docs/next/operations/configuration/platform-package.md
index e4d7b26f..5d56f49b 100644
--- a/content/en/docs/next/operations/configuration/platform-package.md
+++ b/content/en/docs/next/operations/configuration/platform-package.md
@@ -148,6 +148,12 @@ gateway:
 | --- | --- | --- |
 | `scheduling.globalAppTopologySpreadConstraints` | `""` | Global pod topology spread constraints applied to all managed applications. |
 
+#### Backup storage
+
+| Value | Default | Description |
+| --- | --- | --- |
+| `backupStorage` | `{}` | S3 coordinates for the platform-managed `cozy-default` BackupClass. The whole block is forwarded into the `backupstrategy-controller` component and deep-merged over its chart defaults; keys include `provisionBucket`, `bucketName`, `endpoint`, `region`, `forcePathStyle`, `systemSecretName`, and `systemNamespaces`. See [Backup Classes]({{% ref "/docs/next/operations/services/backup-classes" %}}) for the knob-by-knob reference. |
+
 #### Branding
 
 | Value | Default | Description |
diff --git a/content/en/docs/next/operations/services/backup-classes.md b/content/en/docs/next/operations/services/backup-classes.md
index 2d34565f..d21ebb71 100644
--- a/content/en/docs/next/operations/services/backup-classes.md
+++ b/content/en/docs/next/operations/services/backup-classes.md
@@ -114,7 +114,7 @@ Alert on `rate(failures_total) > 0` or `absent_over_time(successes_total[10m])`
 
 ## Admin overrides for `cozy-default`
 
-`cozy-default` is rendered by the `backupstrategy-controller` chart and owned by Flux's helm-controller. **Direct `kubectl edit backupclass cozy-default` is overwritten on the next helm reconcile** — the same applies to its companion `strategy.backups.cozystack.io/*` CRs (`cozy-default-cnpg`, `cozy-default-etcd`, `cozy-default-mariadb`, `cozy-default-altinity`, `cozy-default-foundationdb`, the two `cozy-default-velero-*`). The supported override path is the cozystack `Package` CR, which lets admins inject Helm values into platform components:
+`cozy-default` is rendered by the `backupstrategy-controller` chart and owned by Flux's helm-controller. **Direct `kubectl edit backupclass cozy-default` is overwritten on the next helm reconcile** — the same applies to its companion `strategy.backups.cozystack.io/*` CRs (`cozy-default-cnpg`, `cozy-default-etcd`, `cozy-default-mariadb`, `cozy-default-altinity`, `cozy-default-foundationdb`, the two `cozy-default-velero-*`). The supported override path is the `backupStorage` block on the **`platform` component** of the `cozystack.cozystack-platform` Package CR:
 
 ```yaml
 apiVersion: cozystack.io/v1alpha1
@@ -123,7 +123,7 @@ metadata:
   name: cozystack.cozystack-platform
 spec:
   components:
-    backupstrategy-controller:
+    platform:
       values:
         backupStorage:
           provisionBucket: true                    # default; set false for external S3
@@ -136,6 +136,8 @@ spec:
             - cozy-velero
 ```
 
+The platform chart forwards this block into the child `Package cozystack.backupstrategy-controller` as component values, from where the cozystack operator merges it into the `backupstrategy-controller` HelmRelease over the chart defaults. Two paths that look plausible do **not** work: `spec.components.backupstrategy-controller` on the `cozystack.cozystack-platform` Package is silently ignored (the only component under that PackageSource is `platform`), and patching the child `Package cozystack.backupstrategy-controller` directly is reverted whenever the platform helm-reconcile re-renders it.
+
 | Knob | Effect |
 |---|---|
 | `provisionBucket` | Toggle creation of the in-cluster `apps.cozystack.io/Bucket` CR. Set `false` for external S3 (see [Disabling the platform-managed bucket](#disabling-the-platform-managed-bucket)). |