diff --git a/chromium-setup/emmc-provisioning/cloud-init/config-files/README.md b/chromium-setup/emmc-provisioning/cloud-init/config-files/README.md
index 1707e3f..8f94e00 100644
--- a/chromium-setup/emmc-provisioning/cloud-init/config-files/README.md
+++ b/chromium-setup/emmc-provisioning/cloud-init/config-files/README.md
@@ -8,4 +8,5 @@ first-boot.sh downloads these from `FILE_SERVER` (e.g. `http://10.130.60.141:500
 | 99-default-session.conf | /etc/lightdm/lightdm.conf.d/99-default-session.conf (rpd-labwc) |
 | maliit-keyboard.desktop | /home/pi/.config/autostart/maliit-keyboard.desktop |
 | set-rotation-once.desktop | /home/pi/.config/autostart/set-rotation-once.desktop (with set-rotation-once.sh) |
-| set-wallpaper-once.desktop | /home/pi/.config/autostart/set-wallpaper-once.desktop (with set-wallpaper-once.sh) |
+
+Wallpaper is set once during first-boot by creating `~/.config/labwc/autostart` with swaybg; no set-wallpaper-once one-shot.
diff --git a/chromium-setup/emmc-provisioning/cloud-init/files-from-guard/README.md b/chromium-setup/emmc-provisioning/cloud-init/files-from-guard/README.md
index 801b2b2..7a2e828 100644
--- a/chromium-setup/emmc-provisioning/cloud-init/files-from-guard/README.md
+++ b/chromium-setup/emmc-provisioning/cloud-init/files-from-guard/README.md
@@ -15,7 +15,8 @@ first-boot.sh downloads from **`.../files/first-boot/`** (e.g. `http://10.130.60
 | **99-default-session.conf** | LightDM default session rpd-labwc (from `config-files/`). |
 | **maliit-keyboard.desktop** | Maliit on-screen keyboard autostart (from `config-files/`). |
 | **set-rotation-once.sh** + **.desktop** | One-shot: wlr-randr rotation (Left) at first login. |
-| **set-wallpaper-once.sh** + **.desktop** | One-shot: swaybg wallpaper + labwc autostart at first login. |
+
+Desktop wallpaper is set once during first-boot (labwc autostart created by first-boot.sh); no set-wallpaper-once needed.
 
 ---
 
@@ -25,4 +26,4 @@ first-boot.sh downloads from **`.../files/first-boot/`** (e.g. `http://10.130.60
 - **plymouth-custom/custom.plymouth** — Plymouth theme definition; host as `custom.plymouth`.
 - **plymouth-custom/custom.script** — Plymouth script that draws splash.png; host as `custom.script`.
 - **lightdm/RPiSystem_dark.png** — Unused; only `splash.png` is used now.
-- **set-rotation-once.sh** and **set-wallpaper-once.sh** live in `cloud-init/`; copy them into `portal-files/first-boot/` on the file server.
+- **set-rotation-once.sh** lives in `cloud-init/`; copy it (and its .desktop) into `portal-files/first-boot/` on the file server.
diff --git a/chromium-setup/emmc-provisioning/cloud-init/first-boot.md b/chromium-setup/emmc-provisioning/cloud-init/first-boot.md
index 9d0f1ee..969098b 100644
--- a/chromium-setup/emmc-provisioning/cloud-init/first-boot.md
+++ b/chromium-setup/emmc-provisioning/cloud-init/first-boot.md
@@ -17,7 +17,7 @@ This script runs once on first boot via cloud-init (see `user-data-remote-gnss.e
 9. **reTerminal DM drivers** — Seeed repo clone and `reTerminal.sh`.
 10. **Re-apply splash** — Set `disable_splash=0`, Plymouth theme to `custom` only, `update-initramfs`.
 11. **Boot order** — If `rpi-eeprom-config` is available, set `BOOT_ORDER=0x21` (network first, then eMMC/SD) for future network boot / re-provisioning.
-12. **One-shots** — Download `set-rotation-once.sh` + `.desktop` and `set-wallpaper-once.sh` + `.desktop` from file server (wlr-randr + swaybg for labwc).
+12. **One-shots** — Download `set-rotation-once.sh` + `.desktop` from file server (wlr-randr for labwc). Wallpaper is set once by creating `~/.config/labwc/autostart` during first-boot.
 13. **Reboot.**
 
 ---
@@ -81,7 +81,7 @@ A **single image** (`splash.png`) is used for the boot splash, login screen, and
 
 - **Plymouth (boot splash):** Downloads `splash.png`, `custom.plymouth`, and `custom.script` from the file server → installs to `/usr/share/plymouth/themes/custom/` → sets `Theme=custom` in `/etc/plymouth/plymouthd.conf` (single `[Daemon]` section) → runs `update-initramfs -u`. If any download fails, logs a warning and continues. **Note:** On reTerminal DM the DSI panel can initialize a few seconds into boot, so the Plymouth splash may appear briefly or after a short black screen; this is normal for DSI displays.
 - **LightDM (login screen):** Copies the same image to `/usr/share/rpd-wallpaper/splash.png` and writes `/etc/lightdm/lightdm.conf.d/99-wallpaper.conf` with `wallpaper=...` and `wallpaper_mode=crop`.
-- **Desktop wallpaper:** A one-shot autostart runs when **pi** first logs in: it adds `swaybg -i /usr/share/rpd-wallpaper/splash.png -m fill` to `~/.config/labwc/autostart` (so it persists across logins) and runs swaybg for the current session. The one-shot then deletes itself.
+- **Desktop wallpaper:** First-boot sets the wallpaper once by writing pcmanfm config: `~/.config/pcmanfm/LXDE-pi/desktop-items-0.conf` and `default/desktop-items-0.conf` with `wallpaper=/usr/share/rpd-wallpaper/splash.png` and `wallpaper_mode=crop`. pcmanfm-pi (rpd-labwc desktop) reads this and shows the wallpaper; no autostart script. To set or change wallpaper manually: `pcmanfm --set-wallpaper /path/to/image.png --wallpaper-mode=crop` (modes: crop, stretch, fit, center, tile, screen, color).
 
 ---
 
@@ -142,3 +142,4 @@ Runs **`reboot`** so the kernel and display stack load the new Seeed drivers. Af
 - **Kiosk URL** — The URL Chromium opens is defined in `start-chromium.sh` on your file server (e.g. `--app=http://127.0.0.1:8080`); change it there.
 - **User** — If you use a user other than `pi`, replace `pi` in this script and in the files on the file server (paths and ownership).
 - **Screen rotation** — The one-shot runs `wlr-randr --output <name> --transform 270` (Left). To use another orientation, change `270` to `90` (right), `180` (inverted), or `normal`.
+- **Desktop wallpaper** — First-boot writes `wallpaper=` and `wallpaper_mode=crop` into pcmanfm’s `desktop-items-0.conf`. To change later: `pcmanfm --set-wallpaper /path/to/image --wallpaper-mode=crop`. **Other pcmanfm options:** `pcmanfm --desktop` (start desktop manager), `pcmanfm --desktop-pref` (open desktop preferences GUI), `pcmanfm --desktop-off` (stop desktop manager), `pcmanfm -w FILE` (short form of --set-wallpaper). Wallpaper modes: `crop`, `stretch`, `fit`, `center`, `tile`, `screen`, `color`.
diff --git a/chromium-setup/emmc-provisioning/cloud-init/first-boot.sh b/chromium-setup/emmc-provisioning/cloud-init/first-boot.sh
index 271efb4..c44e703 100644
--- a/chromium-setup/emmc-provisioning/cloud-init/first-boot.sh
+++ b/chromium-setup/emmc-provisioning/cloud-init/first-boot.sh
@@ -94,6 +94,19 @@ if curl -fsSL "${FILE_SERVER}/splash.png" -o "$PLYMOUTH_DIR/splash.png"; then
   update-initramfs -u -k all 2>/dev/null || true
   mkdir -p /etc/lightdm/lightdm.conf.d
   curl -fsSL "${FILE_SERVER}/99-wallpaper.conf" -o /etc/lightdm/lightdm.conf.d/99-wallpaper.conf 2>/dev/null || log "WARNING: Could not download 99-wallpaper.conf"
+  # Set desktop wallpaper once via pcmanfm config (rpd-labwc uses pcmanfm-pi; profile LXDE-pi or default)
+  for PROFILE in LXDE-pi default; do
+    PCMANFM_DESKTOP="$PI_HOME/.config/pcmanfm/$PROFILE/desktop-items-0.conf"
+    mkdir -p "$(dirname "$PCMANFM_DESKTOP")"
+    if [[ ! -f "$PCMANFM_DESKTOP" ]]; then
+      printf '%s\n' '[*]' "wallpaper=$WALLPAPER_PATH" 'wallpaper_mode=crop' 'wallpaper_common=1' > "$PCMANFM_DESKTOP"
+    else
+      grep -q '^wallpaper=' "$PCMANFM_DESKTOP" && sed -i "s|^wallpaper=.*|wallpaper=$WALLPAPER_PATH|" "$PCMANFM_DESKTOP" || echo "wallpaper=$WALLPAPER_PATH" >> "$PCMANFM_DESKTOP"
+      grep -q '^wallpaper_mode=' "$PCMANFM_DESKTOP" && sed -i 's/^wallpaper_mode=.*/wallpaper_mode=crop/' "$PCMANFM_DESKTOP" || echo 'wallpaper_mode=crop' >> "$PCMANFM_DESKTOP"
+    fi
+    chown -R "$PI_USER:$PI_USER" "$(dirname "$PCMANFM_DESKTOP")"
+  done
+  log "Set desktop wallpaper via pcmanfm config (LXDE-pi and default)"
   log "Splash and wallpaper set from file server"
 else
   log "WARNING: Could not download splash.png"
@@ -156,6 +169,14 @@ fi
 log "Running update-initramfs to apply Plymouth theme ..."
 update-initramfs -u -k all 2>/dev/null || true
 
+# --- 6b2. Kernel cmdline: swiotlb for vc4-drm (avoids "swiotlb buffer is full" / blank DSI on CM4) ---
+CMDLINE_PATH="/boot/firmware/cmdline.txt"
+[[ -f "$CMDLINE_PATH" ]] || CMDLINE_PATH="/boot/cmdline.txt"
+if [[ -f "$CMDLINE_PATH" ]] && ! grep -q 'swiotlb=' "$CMDLINE_PATH"; then
+  sed -i 's/rootwait/rootwait swiotlb=65536/' "$CMDLINE_PATH"
+  log "Added swiotlb=65536 to kernel cmdline (vc4-drm / DSI)"
+fi
+
 # --- 6c. Boot order: network first, then eMMC/SD (for future network boot / re-provisioning) ---
 # BOOT_ORDER: 0x2 = network, 0x1 = SD/eMMC. 0x21 = try network first, then local storage.
 log "--- Boot order (network first, then eMMC/SD) ---"
@@ -180,10 +201,9 @@ else
   log "rpi-eeprom-config/rpi-eeprom-update not found; skipping boot order (not a Pi4/CM4 or package missing)"
 fi
 
-# --- 7. One-shots (rotation + wallpaper at first login) ---
+# --- 7. One-shots (rotation at first login; wallpaper already set in pcmanfm config above) ---
 log "--- One-shot scripts (run at pi first login) ---"
 install_oneshot set-rotation-once || true
-install_oneshot set-wallpaper-once || true
 log "One-shots will append to $LOGFILE when they run at first login"
 
 # --- 8. Allow pi to append to first-boot.log (for one-shot scripts) ---
diff --git a/chromium-setup/emmc-provisioning/cloud-init/fix-reterminal-display.sh b/chromium-setup/emmc-provisioning/cloud-init/fix-reterminal-display.sh
index 1ecc838..2492c35 100644
--- a/chromium-setup/emmc-provisioning/cloud-init/fix-reterminal-display.sh
+++ b/chromium-setup/emmc-provisioning/cloud-init/fix-reterminal-display.sh
@@ -29,7 +29,7 @@ update-initramfs -u -k all 2>/dev/null || true
 echo "=== Rotation and wallpaper (rpd-labwc / labwc Wayland) ==="
 echo "To set rotation and wallpaper now (in a labwc session), run as $PI_USER:"
 echo "  wlr-randr --output \$(wlr-randr | awk '/^[A-Za-z0-9_-]+ /{print \$1; exit}') --transform 270"
-echo "  swaybg -i /usr/share/rpd-wallpaper/splash.png -m fill &"
+echo "  pcmanfm --set-wallpaper /usr/share/rpd-wallpaper/splash.png --wallpaper-mode=crop"
 echo ""
 echo "Or ensure one-shots run at next login (they are in autostart if still present)."
 echo "=== Reboot to apply splash and initramfs ==="
diff --git a/chromium-setup/emmc-provisioning/scripts/sync-portal-files-to-lxc.sh b/chromium-setup/emmc-provisioning/scripts/sync-portal-files-to-lxc.sh
index f0f6f26..b523fb8 100755
--- a/chromium-setup/emmc-provisioning/scripts/sync-portal-files-to-lxc.sh
+++ b/chromium-setup/emmc-provisioning/scripts/sync-portal-files-to-lxc.sh
@@ -35,10 +35,9 @@ rsync -avz \
   "$CLOUDINIT_DIR/files-from-guard/plymouth-custom/" \
   "$LXC:$REMOTE_FIRST_BOOT/"
 
-# one-shot scripts from cloud-init root → portal-files/first-boot/
+# one-shot scripts from cloud-init root → portal-files/first-boot/ (wallpaper set in first-boot via labwc autostart)
 rsync -avz \
   "$CLOUDINIT_DIR/set-rotation-once.sh" \
-  "$CLOUDINIT_DIR/set-wallpaper-once.sh" \
   "$LXC:$REMOTE_FIRST_BOOT/"
 
 echo "Done. Portal files at http://$(echo "$LXC" | cut -d@ -f2):5000/files/"