diff --git a/update_psa_helpers b/update_psa_helpers
index 8760bf1..e1b6cd0 100755
--- a/update_psa_helpers
+++ b/update_psa_helpers
@@ -34,14 +34,44 @@ fetch_customer_updates() {
 # Check if the fetched/merged files have the correct md5 and are
 # valid for the PSA.
 #
-check_md5_for_changed_customer_files () {
+check_md5_for_changed_conf_and_ini_files () {
     local func="${FUNCNAME[0]}"
-    #for file in ($1); do
-        # Check the updates for correct MD5
-        # log_error "$func:${LINENO}: new customer files wrong"
-        #    revert_customer_repository ; exit 1
-        # fi
-    #done
+    local json_key=""
+    local md5sum_update_conf=""
+    local md5sum_repository=""
+    log_debug "$func:${LINENO} files=$1"
+    if ! [ -z $1 ]; then
+        readarray -td' ' files <<< "$1"
+        for file in ${files[@]}; do
+            if [ "$file" = "emp.conf" ]; then
+                json_key=".conf.szeged.zg1.z1.etc.psa_config.emp"
+                md5sum_update_conf=$(cat $update_conf | jq -r $json_key)
+                md5sum_repository="$(md5sum $emp_conf | awk '{ print $1}')"
+            elif [ "$file" = "printer.conf" ]; then
+                json_key=".conf.szeged.zg1.z1.etc.psa_config.printer"
+                md5sum_update_conf=$(cat $update_conf | jq -r $json_key)
+                md5sum_repository="$(md5sum $printer_conf | awk '{ print $1}')"
+            elif [ "$file" = "device.conf" ]; then
+                json_key=".conf.szeged.zg1.z1.etc.psa_config.device"
+                md5sum_update_conf=$(cat $update_conf | jq -r $json_key)
+                md5sum_repository="$(md5sum $device_conf | awk '{ print $1}')"
+            else
+                continue
+            fi
+
+            if [ "$md5sum_repository" = "$md5sum_update_conf" ]; then
+                log_info "$func:${LINENO}: md5sum for $file ok"
+            else
+                local __r="repository: $md5sum_repository"
+                local __u="update.conf=$md5sum_update_conf"
+                local __m="$__r != $__u"
+                log_error "$func:${LINENO}: md5sum for $file wrong: $__m"
+                return 1
+            fi
+        done
+    else
+        log_debug "$func:${LINENO} no changed conf-/ini-files"
+    fi
     return 0
 }
 
@@ -82,7 +112,7 @@ check_md5_for_opkg_packages () {
 # In case the new checked-out files are not correct, revert the git
 # repository to its previous state.
 #
-revert_customer_repository() {
+revert_customer_repository () {
     local func="${FUNCNAME[0]}"
     return 0
 }
@@ -137,11 +167,19 @@ exec_opkg_info () {
 # Try to install new opkg-packages (in case the are some
 # in the new git-checkout).
 #
-exec_opkg_no_action() {
+exec_opkg_noaction() {
     local func="${FUNCNAME[0]}"
     local opkg_command_no_action="opkg --noaction $1"
-    log_info "$func:${LINENO}: executing $opkg_command_no_action"
-    return 0
+    log_debug "$func:${LINENO}: executing $opkg_command_no_action"
+    
+    local __opkg_result=$(exec_opkg_command "opkg --noaction $1")
+    if [ $? -eq 0 ]; then
+        log_info "$func:${LINENO}: opkg_result=$__opkg_result"
+        return 0
+    fi
+
+    log_error "$func:${LINENO}: error executing opkg --noaction $1"
+    return 1
 }
 
 # Install the new packages using opkg.