diff --git a/containers/libreportal/frontend/core/setup/js/setup-wizard.js b/containers/libreportal/frontend/core/setup/js/setup-wizard.js
index b2b9bc8..e71fd78 100755
--- a/containers/libreportal/frontend/core/setup/js/setup-wizard.js
+++ b/containers/libreportal/frontend/core/setup/js/setup-wizard.js
@@ -527,6 +527,16 @@ class SetupWizard {
   //
   // The badge carries severity and Details carries the explanation, so the card
   // stays a single row.
+  // What to call the default app-data location. It is the OS disk on a normal
+  // install, but --containers-dir can put it on its own drive, and calling that
+  // "System disk" showed the data drive's size under the system disk's name
+  // while the actual system disk was absent from the list.
+  _primaryLabel() {
+    const s = this.storageSystem;
+    if (!s || s.is_os_disk !== false) return 'System disk';
+    return s.mount && s.mount !== '/' ? s.mount : (s.path || 'Default location');
+  }
+
   _storageCard(c, key, opts) {
     const o = opts || {};
     const refused = c.verdict === 'refuse';
@@ -535,7 +545,7 @@ class SetupWizard {
       : (refused ? '<span class="setup-storage-badge setup-storage-badge-bad">can\u2019t be used</span>'
                  : (c.verdict === 'warn' ? '<span class="setup-storage-badge setup-storage-badge-warn">needs care</span>' : ''));
 
-    const title = o.system ? 'System disk' : c.path;
+    const title = o.system ? this._primaryLabel() : c.path;
 
     return `
       <div class="setup-app setup-storage-card${refused ? ' setup-storage-disabled' : ''} setup-storage-locked">
@@ -553,7 +563,7 @@ class SetupWizard {
 
   // Every place a root could go: the system disk, plus each usable candidate.
   _storageChoices() {
-    const opts = [{ value: 'primary', label: 'System disk' }];
+    const opts = [{ value: 'primary', label: this._primaryLabel() }];
     this.storageCandidates
       .filter(c => c.verdict !== 'refuse')
       .forEach(c => opts.push({ value: c.path, label: c.path }));
@@ -681,7 +691,7 @@ class SetupWizard {
     this.storageCandidates
       .filter(c => c.verdict !== 'refuse')
       .forEach(c => opts.push({ value: c.path, label: c.path, shared: c.path === appTarget }));
-    opts.push({ value: 'primary', label: 'System disk', shared: this.storageDefault === 'primary' });
+    opts.push({ value: 'primary', label: this._primaryLabel(), shared: this.storageDefault === 'primary' });
 
     box.innerHTML = `
       <div class="setup-storage-choice">
@@ -890,7 +900,7 @@ class SetupWizard {
     const m = window.openEoModal({
       id: 'lp-storage-details',
       size: 'md',
-      title: isSystem ? 'System disk' : c.path,
+      title: isSystem ? this._primaryLabel() : c.path,
       desc: `${c.size} drive \u00b7 ${c.free} free \u00b7 ${c.fstype}${c.removable ? ' \u00b7 removable' : ''}`,
       body: parts.join(''),
       actions: [{ label: 'Close', variant: 'secondary' }],
diff --git a/scripts/dev/lp-shot b/scripts/dev/lp-shot
index 4c3fada..66dae89 100755
--- a/scripts/dev/lp-shot
+++ b/scripts/dev/lp-shot
@@ -358,6 +358,24 @@ class CDP:
 
 
 def main():
+    # Print a session cookie and exit. A screenshot is enough for "does it
+    # render", but not for "does this wizard step work" — that needs clicking,
+    # which means driving a real browser, which needs the same session lp-shot
+    # already knows how to mint. Without this the only way in is typing the
+    # admin password into the login form.
+    #
+    #   lp-shot --token            -> the raw cookie VALUE
+    #   lp-shot --cookie-js        -> a document.cookie assignment to paste/eval
+    if len(sys.argv) > 1 and sys.argv[1] in ("--token", "--cookie-js"):
+        token, src = mint_token()
+        if os.environ.get("LP_SHOT_VERBOSE"):
+            print(f"signed from {src}", file=sys.stderr)
+        if sys.argv[1] == "--token":
+            print(token)
+        else:
+            print(f'document.cookie = "{COOKIE}={token}; path=/"')
+        sys.exit(0)
+
     if len(sys.argv) < 2 or sys.argv[1] in ("-h", "--help"):
         print(__doc__.strip())
         sys.exit(0 if len(sys.argv) > 1 else 2)
diff --git a/scripts/webui/data/generators/system/webui_storage_candidates.sh b/scripts/webui/data/generators/system/webui_storage_candidates.sh
index c9327f2..65160a1 100644
--- a/scripts/webui/data/generators/system/webui_storage_candidates.sh
+++ b/scripts/webui/data/generators/system/webui_storage_candidates.sh
@@ -73,6 +73,14 @@ webuiGenerateStorageCandidates()
     local sys_pct; sys_pct=$(df -Pk "$sys_root" 2>/dev/null | awk 'NR==2 {gsub("%","",$5); print $5}')
     system_json+=",\"used_pct\":${sys_pct:-0}"
     system_json+=",\"removable\":false"
+    # Is this entry actually the OS disk? On a default install the app-data root
+    # sits on /, and "System disk" is the honest name for it. Installed with
+    # --containers-dir on another drive it does not, and calling that the system
+    # disk reports the WRONG size (the data drive's) while the real system disk
+    # never appears in the list at all.
+    local sys_is_os=false
+    [[ "$(stat -c '%d' -- "$sys_root" 2>/dev/null)" == "$(stat -c '%d' -- / 2>/dev/null)" ]] && sys_is_os=true
+    system_json+=",\"is_os_disk\":$sys_is_os"
     system_json+=",\"apps\":\"$(_lpJsonEsc "$(storageAppsOnRoot "$sys_root" 2>/dev/null | paste -sd, -)")\""
     system_json+=",\"checks\":$sys_checks}"