diff --git a/re/udsscanwindow.cpp b/re/udsscanwindow.cpp
index 619691b..9ff8a7d 100644
--- a/re/udsscanwindow.cpp
+++ b/re/udsscanwindow.cpp
@@ -117,7 +117,7 @@ void UDSScanWindow::readByToggled()
 
 void UDSScanWindow::numBytesChanged()
 {
-    uint64_t upperBound =  (1 << (8 * ui->spinNumBytes->value())) - 1;
+    uint64_t upperBound =  (1ull << (8ull * ui->spinNumBytes->value())) - 1;
     if (upperBound > 0x7FFFFFFF) upperBound = 0x7FFFFFFF;
     ui->spinUpperSubfunc->setMaximum(upperBound);
 }
diff --git a/ui/udsscanwindow.ui b/ui/udsscanwindow.ui
index f0f8195..cae150e 100644
--- a/ui/udsscanwindow.ui
+++ b/ui/udsscanwindow.ui
@@ -260,6 +260,9 @@
        <property name="enabled">
         <bool>false</bool>
        </property>
+       <property name="prefix">
+        <string>0x</string>
+       </property>
        <property name="maximum">
         <number>255</number>
        </property>
@@ -280,6 +283,9 @@
        <property name="enabled">
         <bool>false</bool>
        </property>
+       <property name="prefix">
+        <string>0x</string>
+       </property>
        <property name="maximum">
         <number>255</number>
        </property>
@@ -330,6 +336,9 @@
        <property name="enabled">
         <bool>false</bool>
        </property>
+       <property name="prefix">
+        <string>0x</string>
+       </property>
        <property name="maximum">
         <number>255</number>
        </property>
@@ -350,6 +359,9 @@
        <property name="enabled">
         <bool>false</bool>
        </property>
+       <property name="prefix">
+        <string>0x</string>
+       </property>
        <property name="maximum">
         <number>255</number>
        </property>