diff --git a/services/net/src/connection_manager.rs b/services/net/src/connection_manager.rs
index 20586e0a7..9037e9043 100644
--- a/services/net/src/connection_manager.rs
+++ b/services/net/src/connection_manager.rs
@@ -62,7 +62,7 @@ pub(crate) fn connection_manager(sid: xous::SID, activity_interval: Arc<AtomicU3
     let xns = xous_names::XousNames::new().unwrap();
     let mut com = com::Com::new(&xns).unwrap();
     let netmgr = net::NetManager::new();
-    let mut pddb = pddb::Pddb::new();
+    let pddb = pddb::Pddb::new();
     let self_cid = xous::connect(sid).unwrap();
     // give the system some time to boot before trying to run a check on the EC minimum version, as it is in reset on boot
     tt.sleep_ms(POLL_INTERVAL_MS).unwrap();
diff --git a/services/pddb/src/lib.rs b/services/pddb/src/lib.rs
index b53fbd16a..bc9d4cdc2 100644
--- a/services/pddb/src/lib.rs
+++ b/services/pddb/src/lib.rs
@@ -495,7 +495,7 @@ impl Pddb {
         }
     }
 
-    pub fn list_keys(&mut self, dict_name: &str, basis_name: Option<&str>) -> Result<Vec::<String>> {
+    pub fn list_keys(&self, dict_name: &str, basis_name: Option<&str>) -> Result<Vec::<String>> {
         if dict_name.len() > (DICT_NAME_LEN - 1) {
             return Err(Error::new(ErrorKind::InvalidInput, "dictionary name too long"));
         }
@@ -557,7 +557,7 @@ impl Pddb {
     }
 
 
-    pub fn list_dict(&mut self, basis_name: Option<&str>) -> Result<Vec::<String>> {
+    pub fn list_dict(&self, basis_name: Option<&str>) -> Result<Vec::<String>> {
         let bname = if let Some(bname) = basis_name {
             if bname.len() > BASIS_NAME_LEN - 1 {
                 return Err(Error::new(ErrorKind::InvalidInput, "basis name too long"));
diff --git a/services/shellchat/src/cmds/wlan.rs b/services/shellchat/src/cmds/wlan.rs
index 8deeed431..2b590a59b 100644
--- a/services/shellchat/src/cmds/wlan.rs
+++ b/services/shellchat/src/cmds/wlan.rs
@@ -121,7 +121,7 @@ impl<'a> ShellCmdApi<'a> for Wlan {
                     }
                 }
                 "known" => {
-                    let mut pddb = pddb::Pddb::new();
+                    let pddb = pddb::Pddb::new();
                     match pddb.list_keys(net::AP_DICT_NAME, None) {
                         Ok(list) => {
                             write!(ret, "Saved network configs:\n").unwrap();