diff --git a/modules/firmware.sh b/modules/firmware.sh
index 7d20a26..7394e78 100644
--- a/modules/firmware.sh
+++ b/modules/firmware.sh
@@ -340,7 +340,17 @@ _ensure_nonfree_repo() {
         return 0
     fi
 
-    if _confirm "non-free Repository" "Component 'non-free' (and 'non-free-firmware') is required for WiFi/Bluetooth/GPU firmware.\n\nAdd them to your APT repositories?"; then
+    if ! _confirm "non-free Repository" "Component 'non-free' (and 'non-free-firmware') is required for WiFi/Bluetooth/GPU firmware.\n\nAdd them to your APT repositories?"; then
+        return 1
+    fi
+
+    # No active sources at all → bootstrap a complete configuration
+    if ! has_active_deb_sources; then
+        backup_current_repos
+        if ! bootstrap_repositories "main contrib non-free non-free-firmware"; then
+            return 1
+        fi
+    else
         if [ -f /etc/apt/sources.list ]; then
             sudo sed -i '/^deb / { /non-free/! s/\(main[^ ]*\)/\1 non-free non-free-firmware/ }' /etc/apt/sources.list
         fi
@@ -350,11 +360,21 @@ _ensure_nonfree_repo() {
                 sudo sed -i '/^Components:/ { /non-free/! s/$/ non-free non-free-firmware/ }' "$f"
             done
         fi
-        sudo apt update
-        echo -e "${GREEN}non-free repository enabled.${NC}"
-        return 0
     fi
-    return 1
+
+    # Verify the component was actually added before reporting success
+    local nonfree_ok=false
+    [ -f /etc/apt/sources.list ] && grep -Eq '^[^#]*\bnon-free\b' /etc/apt/sources.list 2>/dev/null && nonfree_ok=true
+    [ -d /etc/apt/sources.list.d ] && grep -qr 'Components:.*\bnon-free\b' /etc/apt/sources.list.d/*.sources 2>/dev/null && nonfree_ok=true
+    [ -d /etc/apt/sources.list.d ] && grep -qrE '^[^#]*\bnon-free\b' /etc/apt/sources.list.d/*.list 2>/dev/null && nonfree_ok=true
+    if ! $nonfree_ok; then
+        echo -e "${RED}Failed to enable non-free repository. Check your APT sources.${NC}"
+        return 1
+    fi
+
+    sudo apt update
+    echo -e "${GREEN}non-free repository enabled.${NC}"
+    return 0
 }
 
 # ── Main entry point ──
diff --git a/modules/gaming.sh b/modules/gaming.sh
index 860943a..8bef5cf 100644
--- a/modules/gaming.sh
+++ b/modules/gaming.sh
@@ -27,7 +27,18 @@ ensure_contrib_repo() {
         return 0
     fi
 
-    if _confirm "contrib Repository" "Component 'contrib' is required for Steam.\n\nAdd 'contrib' to your APT repositories?"; then
+    if ! _confirm "contrib Repository" "Component 'contrib' is required for Steam.\n\nAdd 'contrib' to your APT repositories?"; then
+        echo -e "${YELLOW}contrib repository not enabled. Steam installation may fail.${NC}"
+        return 1
+    fi
+
+    # No active sources at all → bootstrap a complete configuration
+    if ! has_active_deb_sources; then
+        backup_current_repos
+        if ! bootstrap_repositories "main contrib"; then
+            return 1
+        fi
+    else
         if [ -f /etc/apt/sources.list ]; then
             sudo sed -i '/^deb / { /contrib/! s/main/main contrib/ }' /etc/apt/sources.list
         fi
@@ -37,13 +48,21 @@ ensure_contrib_repo() {
                 sudo sed -i '/^Components:/ { /contrib/! s/$/ contrib/ }' "$f"
             done
         fi
-        sudo apt update
-        echo -e "${GREEN}contrib repository enabled.${NC}"
-        return 0
     fi
 
-    echo -e "${YELLOW}contrib repository not enabled. Steam installation may fail.${NC}"
-    return 1
+    # Verify the component was actually added before reporting success
+    local contrib_ok=false
+    [ -f /etc/apt/sources.list ] && grep -Eq '^[^#]*\bcontrib\b' /etc/apt/sources.list 2>/dev/null && contrib_ok=true
+    [ -d /etc/apt/sources.list.d ] && grep -qr 'Components:.*\bcontrib\b' /etc/apt/sources.list.d/*.sources 2>/dev/null && contrib_ok=true
+    [ -d /etc/apt/sources.list.d ] && grep -qrE '^[^#]*\bcontrib\b' /etc/apt/sources.list.d/*.list 2>/dev/null && contrib_ok=true
+    if ! $contrib_ok; then
+        echo -e "${RED}Failed to enable contrib repository. Check your APT sources.${NC}"
+        return 1
+    fi
+
+    sudo apt update
+    echo -e "${GREEN}contrib repository enabled.${NC}"
+    return 0
 }
 
 install_gaming() {
diff --git a/modules/repos.sh b/modules/repos.sh
index c0a9a0e..89fbc32 100644
--- a/modules/repos.sh
+++ b/modules/repos.sh
@@ -353,18 +353,93 @@ _repos_offer_upgrade() {
     fi
 }
 
+# Bootstrap a complete repository configuration from scratch when no active
+# sources exist. Caller must run backup_current_repos() first so that a failed
+# apt update can restore the previous state.
+# Returns: 0 on success, 1 if skipped, declined or failed
+bootstrap_repositories() {
+    local components="$1"
+    local bp_enabled="${2:-false}"
+    local bp_location="${3:-none}"
+
+    if [ -z "$DEBIAN_CODENAME" ]; then
+        _msg "Error" "Cannot bootstrap repositories: Debian codename unknown." 10 65
+        return 1
+    fi
+
+    # non-free-firmware does not exist on Bullseye
+    if [ "$DEBIAN_VERSION" = "11" ]; then
+        components=$(echo "$components" | sed 's/ non-free-firmware//g')
+    fi
+
+    if ! _confirm "Bootstrap Repositories" \
+        "No active APT sources were found (empty or missing sources.list).\n\n\
+Configure repositories from scratch?" 10 65; then
+        echo "Repository configuration skipped."
+        cleanup_repo_backup
+        return 1
+    fi
+
+    if has_active_deb_sources; then
+        if ! _confirm "Custom Sources Found" \
+            "Active sources exist in other files (e.g. sources.list.d/*.sources).\n\n\
+Adding deb.debian.org may duplicate your current mirror configuration. Continue?" 10 65; then
+            cleanup_repo_backup
+            return 1
+        fi
+    fi
+
+    # DEB822 is Trixie-only; Debian 11/12 always use classic
+    local use_deb822=false
+    if [ "$DEBIAN_VERSION" = "13" ]; then
+        local choice
+        choice=$(_menu "Repo Format" "Choose the repository format:" 12 60 3 \
+            "deb822" "Native DEB822 format (sources.list.d/debian.sources)" \
+            "classic" "Classic format (/etc/apt/sources.list)")
+        if [ "$choice" = "deb822" ]; then
+            use_deb822=true
+        fi
+    fi
+
+    if $use_deb822; then
+        _write_deb822 "$DEBIAN_CODENAME" "write" "$bp_enabled" "$bp_location" "$components" || { cleanup_repo_backup; return 1; }
+    else
+        _write_classic "$DEBIAN_CODENAME" "write" "$bp_enabled" "$bp_location" "$components" || { cleanup_repo_backup; return 1; }
+    fi
+
+    # Tidy: with deb822 chosen, an empty classic file is no longer needed
+    if $use_deb822 && [ -f /etc/apt/sources.list ] && ! grep -qE '^[^#]*\bdeb\b' /etc/apt/sources.list 2>/dev/null; then
+        if _confirm "Disable Classic" "An empty /etc/apt/sources.list is no longer needed. Move it aside (sources.list.disabled)?"; then
+            sudo mv /etc/apt/sources.list /etc/apt/sources.list.disabled
+            echo "Empty sources.list renamed to sources.list.disabled"
+        fi
+    fi
+
+    echo "Updating package lists..."
+    if sudo apt update; then
+        REPOS_CONFIGURED=true
+        cleanup_repo_backup
+        echo -e "${GREEN}Repository components configured.${NC}"
+        return 0
+    else
+        restore_previous_repos
+        echo -e "${RED}apt update failed. Previous configuration restored.${NC}"
+        return 1
+    fi
+}
+
 _repos_enable_components() {
     local current_format bp_enabled bp_location components
     current_format=$(detect_repo_format)
 
     if _components_enabled; then
-        if ! _confirm "Disable Components" \
+        if _confirm "Disable Components" \
             "Contrib and non-free are already enabled. Disable them?"; then
-            echo "No changes made."
-            _pause
-            return
+            components="main"
+        else
+            components=$(detect_active_components)
+            echo "Keeping current components: $components"
         fi
-        components="main"
     else
         if ! _confirm "Enable Components" \
             "Enable contrib and non-free components?\n\n\
@@ -390,7 +465,32 @@ popular software (like gaming platforms and proprietary tools)." 12 60; then
 
     backup_current_repos
 
-    if [ "$current_format" = "deb822" ] || [ "$current_format" = "none" ]; then
+    if [ "$current_format" = "none" ]; then
+        if ! bootstrap_repositories "$components" "$bp_enabled" "$bp_location"; then
+            _pause
+            return
+        fi
+        _repos_offer_upgrade
+        echo -e "${GREEN}Cleaning old packages...${NC}"
+        sudo apt autoremove -y
+        sudo apt autoclean
+        echo -e "${GREEN}System packages cleaned.${NC}"
+        _pause
+        return
+    fi
+
+    echo "Verifying repository configuration (main, updates, security)..."
+    if [ "$current_format" = "deb822" ]; then
+        # Mixed-state guard: active classic lines alongside deb822 would duplicate sources
+        if [ -f /etc/apt/sources.list ] && grep -qE '^[^#]*\bdeb\b' /etc/apt/sources.list 2>/dev/null; then
+            if ! _confirm "Duplicate Config" \
+                "Active classic sources were also found in /etc/apt/sources.list.\n\n\
+Writing debian.sources may duplicate your configuration. Continue?" 10 65; then
+                echo "No changes made."
+                _pause
+                return
+            fi
+        fi
         _write_deb822 "$DEBIAN_CODENAME" "write" "$bp_enabled" "$bp_location" "$components"
     else
         _write_classic "$DEBIAN_CODENAME" "write" "$bp_enabled" "$bp_location" "$components"
diff --git a/modules/repos/repo_detect.sh b/modules/repos/repo_detect.sh
index c16d51d..0b4350b 100644
--- a/modules/repos/repo_detect.sh
+++ b/modules/repos/repo_detect.sh
@@ -2,34 +2,76 @@
 # repo_detect.sh – Detection-only helpers for idempotent repository configuration.
 # Part A of the two-part architecture. No user dialogs, no writes.
 
-# Detect the format of the main repo file
+# Any active (non-commented) source of any format, in any file?
+# Returns: 0 if at least one active source exists, 1 otherwise
+has_active_deb_sources() {
+    local f
+    for f in /etc/apt/sources.list /etc/apt/sources.list.d/*.list; do
+        [ -f "$f" ] || continue
+        grep -qE '^[^#]*\bdeb\b' "$f" 2>/dev/null && return 0
+    done
+    for f in /etc/apt/sources.list.d/*.sources; do
+        [ -f "$f" ] || continue
+        grep -qE '^Types:.*\bdeb\b' "$f" 2>/dev/null && \
+            grep -qE '^URIs:' "$f" 2>/dev/null && return 0
+    done
+    return 1
+}
+
+# Detect the format of the main repo file (content-aware).
+# DEB822 is only valid on Debian 13 (Trixie); Debian 11/12 are classic-only.
 # Returns: "deb822", "classic", or "none"
 detect_repo_format() {
-    if [ -f /etc/apt/sources.list.d/debian.sources ]; then
+    if [ "$DEBIAN_VERSION" = "13" ] && [ -f /etc/apt/sources.list.d/debian.sources ] && \
+       grep -qE '^Types:.*\bdeb\b' /etc/apt/sources.list.d/debian.sources 2>/dev/null; then
         echo "deb822"
-    elif [ -f /etc/apt/sources.list ]; then
+    elif [ -f /etc/apt/sources.list ] && grep -qE '^[^#]*\bdeb\b' /etc/apt/sources.list 2>/dev/null; then
         echo "classic"
     else
         echo "none"
     fi
 }
 
-# Check whether backports are currently enabled (any format)
+# Detect the components currently active in the main repo file
+# Returns: components list (e.g. "main contrib non-free non-free-firmware")
+detect_active_components() {
+    if [ "$DEBIAN_VERSION" = "13" ] && [ -f /etc/apt/sources.list.d/debian.sources ]; then
+        local comps
+        comps=$(grep "^Components:" /etc/apt/sources.list.d/debian.sources 2>/dev/null | head -1 | cut -d: -f2- | sed 's/^[[:space:]]*//')
+        if [ -n "$comps" ]; then
+            echo "$comps"
+            return
+        fi
+    fi
+    if [ -f /etc/apt/sources.list ]; then
+        local comps
+        comps=$(grep "^[^#]*deb .* main" /etc/apt/sources.list 2>/dev/null | head -1 | sed 's/.*main\s*//')
+        if [ -n "$comps" ]; then
+            echo "main $comps"
+            return
+        fi
+    fi
+    if [ "$DEBIAN_VERSION" = "11" ]; then
+        echo "main contrib non-free"
+    else
+        echo "main contrib non-free non-free-firmware"
+    fi
+}
+
+# Check whether backports are currently enabled (any format, any file)
 # Returns: 0 if enabled, 1 otherwise
 detect_backports_status() {
     local codename="$1"
 
-    if [ -f /etc/apt/sources.list.d/debian.sources ]; then
+    if [ "$DEBIAN_VERSION" = "13" ] && [ -f /etc/apt/sources.list.d/debian.sources ]; then
         grep -qE "^Suites:.*${codename}-backports" /etc/apt/sources.list.d/debian.sources 2>/dev/null && return 0
     fi
     if [ -f /etc/apt/sources.list ]; then
         grep -qE "^[^#]*${codename}-backports" /etc/apt/sources.list 2>/dev/null && return 0
     fi
-    if [ -f /etc/apt/sources.list.d/debian-backports.sources ]; then
-        grep -qE "^Suites:.*${codename}-backports" /etc/apt/sources.list.d/debian-backports.sources 2>/dev/null && return 0
-    fi
-    if [ -f /etc/apt/sources.list.d/debian-backports.list ]; then
-        grep -qE "^[^#]*${codename}-backports" /etc/apt/sources.list.d/debian-backports.list 2>/dev/null && return 0
+    if [ -d /etc/apt/sources.list.d ]; then
+        grep -qrE "^Suites:.*${codename}-backports" /etc/apt/sources.list.d/*.sources 2>/dev/null && return 0
+        grep -qrE "^[^#]*${codename}-backports" /etc/apt/sources.list.d/*.list 2>/dev/null && return 0
     fi
 
     return 1
@@ -44,18 +86,26 @@ detect_backports_status() {
 detect_backports_location() {
     local codename="$1"
 
-    if [ -f /etc/apt/sources.list.d/debian-backports.sources ] && \
+    if [ "$DEBIAN_VERSION" = "13" ] && [ -f /etc/apt/sources.list.d/debian-backports.sources ] && \
        grep -qE "^Suites:.*${codename}-backports" /etc/apt/sources.list.d/debian-backports.sources 2>/dev/null; then
         echo "standalone-deb822"
     elif [ -f /etc/apt/sources.list.d/debian-backports.list ] && \
          grep -qE "^[^#]*${codename}-backports" /etc/apt/sources.list.d/debian-backports.list 2>/dev/null; then
         echo "standalone-classic"
-    elif [ -f /etc/apt/sources.list.d/debian.sources ] && \
+    elif [ "$DEBIAN_VERSION" = "13" ] && [ -f /etc/apt/sources.list.d/debian.sources ] && \
          grep -qE "^Suites:.*${codename}-backports" /etc/apt/sources.list.d/debian.sources 2>/dev/null; then
         echo "embedded-deb822"
     elif [ -f /etc/apt/sources.list ] && \
          grep -qE "^[^#]*${codename}-backports" /etc/apt/sources.list 2>/dev/null; then
         echo "embedded-classic"
+    elif [ -d /etc/apt/sources.list.d ]; then
+        if grep -qrE "^Suites:.*${codename}-backports" /etc/apt/sources.list.d/*.sources 2>/dev/null; then
+            echo "embedded-deb822"
+        elif grep -qrE "^[^#]*${codename}-backports" /etc/apt/sources.list.d/*.list 2>/dev/null; then
+            echo "embedded-classic"
+        else
+            echo "none"
+        fi
     else
         echo "none"
     fi
diff --git a/modules/utils.sh b/modules/utils.sh
index 3e6eb9a..f5d07a4 100644
--- a/modules/utils.sh
+++ b/modules/utils.sh
@@ -505,14 +505,13 @@ is_backports_enabled() {
         echo true; return
     fi
 
-    # Classic standalone (new — debian-backports.list)
-    if [ -f /etc/apt/sources.list.d/debian-backports.list ] && \
-       grep -Eq "$c_pattern" /etc/apt/sources.list.d/debian-backports.list 2>/dev/null; then
+    # Classic standalone (any .list file in sources.list.d)
+    if [ -d /etc/apt/sources.list.d ] && grep -qrE "$c_pattern" /etc/apt/sources.list.d/*.list 2>/dev/null; then
         echo true; return
     fi
 
     # Deb822 any .sources file
-    if grep -qr "$d_pattern" /etc/apt/sources.list.d/*.sources 2>/dev/null; then
+    if [ -d /etc/apt/sources.list.d ] && grep -qr "$d_pattern" /etc/apt/sources.list.d/*.sources 2>/dev/null; then
         echo true; return
     fi