diff --git a/usr/local/bin/install_to_disk.sh b/usr/local/bin/install_to_disk.sh
index c2f986f..f21e51c 100755
--- a/usr/local/bin/install_to_disk.sh
+++ b/usr/local/bin/install_to_disk.sh
@@ -286,12 +286,19 @@ install_grub() {
     fi
 
     # Install GRUB for UEFI (must succeed)
+    # Use --removable flag to install to default EFI fallback location
     log "  Installing GRUB for UEFI boot..."
-    if ! sudo arch-chroot "$mount_point" grub-install --target=x86_64-efi --efi-directory=/boot --bootloader-id=STORMUX-HDD --recheck 2>&1 | tee -a "$LOGFILE"; then
+    if ! sudo arch-chroot "$mount_point" grub-install --target=x86_64-efi --efi-directory=/boot --bootloader-id=STORMUX-HDD --recheck --removable 2>&1 | tee -a "$LOGFILE"; then
         error_exit "UEFI GRUB installation failed"
     fi
     log "  UEFI boot installation succeeded"
 
+    # Verify /etc/default/grub exists before generating config
+    if [[ ! -f "$mount_point/etc/default/grub" ]]; then
+        log_error "/etc/default/grub not found on target system"
+        error_exit "Cannot generate GRUB config without /etc/default/grub"
+    fi
+
     # Generate GRUB configuration
     log "  Generating GRUB configuration..."
     if ! sudo arch-chroot "$mount_point" grub-mkconfig -o /boot/grub/grub.cfg 2>&1 | tee -a "$LOGFILE"; then