diff --git a/packages/base/any/onlp/src/onlp/module/src/fan.c b/packages/base/any/onlp/src/onlp/module/src/fan.c
index 549814db..a13f6fdc 100644
--- a/packages/base/any/onlp/src/onlp/module/src/fan.c
+++ b/packages/base/any/onlp/src/onlp/module/src/fan.c
@@ -310,10 +310,10 @@ onlp_fan_show(onlp_oid_t oid, aim_pvs_t* pvs, uint32_t flags)
             else {
                 iof_iprintf(&iof, "Status: Running");
                 if(fi.model[0]) {
-                    iof_iprintf(&iof, "Model: %s", fi.model);
+                    iof_iprintf(&iof, "Model: %{pstr}", fi.model, '?');
                 }
                 if(fi.serial[0]) {
-                    iof_iprintf(&iof, "SN: %s", fi.serial);
+                    iof_iprintf(&iof, "SN: %{pstr}", fi.serial, '?');
                 }
                 if(fi.caps & ONLP_FAN_CAPS_GET_RPM) {
                     iof_iprintf(&iof, "RPM: %d", fi.rpm);
@@ -336,4 +336,3 @@ onlp_fan_show(onlp_oid_t oid, aim_pvs_t* pvs, uint32_t flags)
     }
     iof_pop(&iof);
 }
-
diff --git a/packages/base/any/onlp/src/onlp/module/src/psu.c b/packages/base/any/onlp/src/onlp/module/src/psu.c
index 7cba92ad..cd8d9ff8 100644
--- a/packages/base/any/onlp/src/onlp/module/src/psu.c
+++ b/packages/base/any/onlp/src/onlp/module/src/psu.c
@@ -196,8 +196,8 @@ onlp_psu_show(onlp_oid_t id, aim_pvs_t* pvs, uint32_t flags)
             }
             else {
                 iof_iprintf(&iof, "Status: Running");
-                if(pi.model[0]) iof_iprintf(&iof, "Model: %s", pi.model);
-                if(pi.serial[0]) iof_iprintf(&iof, "SN: %s", pi.serial);
+                if(pi.model[0]) iof_iprintf(&iof, "Model: %{pstr}", pi.model, '?');
+                if(pi.serial[0]) iof_iprintf(&iof, "SN: %{pstr}", pi.serial, '?');
                 if(pi.caps & ONLP_PSU_CAPS_AC) {
                     iof_iprintf(&iof, "Type: AC");
                 }