diff --git a/lib/ibutton/protocols/dallas/protocol_ds1971.c b/lib/ibutton/protocols/dallas/protocol_ds1971.c
index d60803fc6..6d147d28d 100644
--- a/lib/ibutton/protocols/dallas/protocol_ds1971.c
+++ b/lib/ibutton/protocols/dallas/protocol_ds1971.c
@@ -218,19 +218,15 @@ void dallas_ds1971_render_uid(FuriString* result, const iButtonProtocolData* pro
 
 void dallas_ds1971_render_data(FuriString* result, const iButtonProtocolData* protocol_data) {
     const DS1971ProtocolData* data = protocol_data;
-    FuriString* data_string = furi_string_alloc();
+
+    furi_string_cat_printf(result, "\e#Memory Data\n--------------------\n");
 
     pretty_format_bytes_hex_canonical(
-        data_string,
+        result,
         DS1971_DATA_BYTE_COUNT,
         PRETTY_FORMAT_FONT_MONOSPACE,
         data->eeprom_data,
         DS1971_EEPROM_DATA_SIZE);
-
-    furi_string_cat_printf(result, "\e#Memory Data\n--------------------\n");
-    furi_string_cat_printf(result, "%s", furi_string_get_cstr(data_string));
-
-    furi_string_free(data_string);
 }
 
 void dallas_ds1971_render_brief_data(FuriString* result, const iButtonProtocolData* protocol_data) {
diff --git a/lib/ibutton/protocols/dallas/protocol_ds1992.c b/lib/ibutton/protocols/dallas/protocol_ds1992.c
index 5ddd8ef2c..483d9827f 100644
--- a/lib/ibutton/protocols/dallas/protocol_ds1992.c
+++ b/lib/ibutton/protocols/dallas/protocol_ds1992.c
@@ -191,19 +191,15 @@ void dallas_ds1992_render_uid(FuriString* result, const iButtonProtocolData* pro
 
 void dallas_ds1992_render_data(FuriString* result, const iButtonProtocolData* protocol_data) {
     const DS1992ProtocolData* data = protocol_data;
-    FuriString* data_string = furi_string_alloc();
+
+    furi_string_cat_printf(result, "\e#Memory Data\n--------------------\n");
 
     pretty_format_bytes_hex_canonical(
-        data_string,
+        result,
         DS1992_DATA_BYTE_COUNT,
         PRETTY_FORMAT_FONT_MONOSPACE,
         data->sram_data,
         DS1992_SRAM_DATA_SIZE);
-
-    furi_string_cat_printf(result, "\e#Memory Data\n--------------------\n");
-    furi_string_cat_printf(result, "%s", furi_string_get_cstr(data_string));
-
-    furi_string_free(data_string);
 }
 
 void dallas_ds1992_render_brief_data(FuriString* result, const iButtonProtocolData* protocol_data) {
diff --git a/lib/ibutton/protocols/dallas/protocol_ds1996.c b/lib/ibutton/protocols/dallas/protocol_ds1996.c
index 6af61f355..157dc601a 100644
--- a/lib/ibutton/protocols/dallas/protocol_ds1996.c
+++ b/lib/ibutton/protocols/dallas/protocol_ds1996.c
@@ -217,19 +217,14 @@ void dallas_ds1996_render_uid(FuriString* result, const iButtonProtocolData* pro
 void dallas_ds1996_render_data(FuriString* result, const iButtonProtocolData* protocol_data) {
     const DS1996ProtocolData* data = protocol_data;
 
-    FuriString* data_string = furi_string_alloc();
+    furi_string_cat_printf(result, "\e#Memory Data\n--------------------\n");
 
     pretty_format_bytes_hex_canonical(
-        data_string,
+        result,
         DS1996_DATA_BYTE_COUNT,
         PRETTY_FORMAT_FONT_MONOSPACE,
         data->sram_data,
         DS1996_SRAM_DATA_SIZE);
-
-    furi_string_cat_printf(result, "\e#Memory Data\n--------------------\n");
-    furi_string_cat_printf(result, "%s", furi_string_get_cstr(data_string));
-
-    furi_string_free(data_string);
 }
 
 void dallas_ds1996_render_brief_data(FuriString* result, const iButtonProtocolData* protocol_data) {
diff --git a/lib/toolbox/pretty_format.c b/lib/toolbox/pretty_format.c
index 2dcfdb6d9..f8319b69d 100644
--- a/lib/toolbox/pretty_format.c
+++ b/lib/toolbox/pretty_format.c
@@ -28,8 +28,7 @@ void pretty_format_bytes_hex_canonical(
     const size_t line_length = (line_prefix ? strlen(line_prefix) : 0) + 4 * num_places + 2;
 
     /* Reserve memory in adance in order to avoid unnecessary reallocs */
-    furi_string_reset(result);
-    furi_string_reserve(result, line_count * line_length);
+    furi_string_reserve(result, furi_string_size(result) + line_count * line_length);
 
     for(size_t i = 0; i < data_size; i += num_places) {
         if(line_prefix) {
diff --git a/lib/toolbox/protocols/protocol_dict.c b/lib/toolbox/protocols/protocol_dict.c
index b66d35335..71fa4fe28 100644
--- a/lib/toolbox/protocols/protocol_dict.c
+++ b/lib/toolbox/protocols/protocol_dict.c
@@ -203,7 +203,7 @@ void protocol_dict_render_uid(ProtocolDict* dict, FuriString* result, size_t pro
     ProtocolRenderData fn = dict->base[protocol_index]->render_uid;
 
     if(fn) {
-        return fn(dict->data[protocol_index], result);
+        fn(dict->data[protocol_index], result);
     }
 }
 
@@ -212,7 +212,7 @@ void protocol_dict_render_data(ProtocolDict* dict, FuriString* result, size_t pr
     ProtocolRenderData fn = dict->base[protocol_index]->render_data;
 
     if(fn) {
-        return fn(dict->data[protocol_index], result);
+        fn(dict->data[protocol_index], result);
     }
 }
 
@@ -221,7 +221,7 @@ void protocol_dict_render_brief_data(ProtocolDict* dict, FuriString* result, siz
     ProtocolRenderData fn = dict->base[protocol_index]->render_brief_data;
 
     if(fn) {
-        return fn(dict->data[protocol_index], result);
+        fn(dict->data[protocol_index], result);
     }
 }