diff --git a/components/sdmmc/sdmmc_cmd.c b/components/sdmmc/sdmmc_cmd.c
index eb9622521df..a36029306c9 100644
--- a/components/sdmmc/sdmmc_cmd.c
+++ b/components/sdmmc/sdmmc_cmd.c
@@ -394,7 +394,7 @@ esp_err_t sdmmc_send_cmd_send_scr(sdmmc_card_t* card, sdmmc_scr_t *out_scr)
     if (err == ESP_OK) {
         err = sdmmc_decode_scr(buf, out_scr);
     }
-    free(buf);
+    heap_caps_free(buf);
     return err;
 }
 
@@ -464,16 +464,15 @@ esp_err_t sdmmc_send_cmd_num_of_written_blocks(sdmmc_card_t* card, size_t* out_n
 
     err = sdmmc_send_app_cmd(card, &cmd);
     if (err != ESP_OK) {
-        free(buf);
+        heap_caps_free(buf);
         ESP_LOGE(TAG, "%s: sdmmc_send_app_cmd returned 0x%x, failed to get number of written write blocks", __func__, err);
         return err;
     }
 
-    size_t result = __builtin_bswap32(*(uint32_t*)buf);
     if (out_num_blocks) {
-        *out_num_blocks = result;
+        *out_num_blocks = __builtin_bswap32(*(uint32_t*)buf);
     }
-    free(buf);
+    heap_caps_free(buf);
     return err;
 }
 
@@ -542,7 +541,7 @@ esp_err_t sdmmc_write_sectors(sdmmc_card_t* card, const void* src,
             }
         }
         if (!use_dma_aligned_buffer) {
-            free(buf);
+            heap_caps_free(buf);
         }
     }
     return err;
@@ -705,7 +704,7 @@ esp_err_t sdmmc_read_sectors(sdmmc_card_t* card, void* dst,
             cur_dst += block_size * blocks_per_read;
         }
         if (!use_dma_aligned_buffer) {
-            free(buf);
+            heap_caps_free(buf);
         }
     }
     return err;
diff --git a/components/sdmmc/sdmmc_mmc.c b/components/sdmmc/sdmmc_mmc.c
index 24bbe9ef9f5..b76308bbd5f 100644
--- a/components/sdmmc/sdmmc_mmc.c
+++ b/components/sdmmc/sdmmc_mmc.c
@@ -98,7 +98,7 @@ esp_err_t sdmmc_init_mmc_read_ext_csd(sdmmc_card_t* card)
     card->ext_csd.sec_feature = ext_csd[EXT_CSD_SEC_FEATURE_SUPPORT];
 
 out:
-    free(ext_csd);
+    heap_caps_free(ext_csd);
     return err;
 }
 
@@ -194,7 +194,7 @@ esp_err_t sdmmc_mmc_decode_csd(sdmmc_response_t response, sdmmc_csd_t* out_csd)
         out_csd->read_block_len = MMC_CSD_READ_BL_LEN(response);
     } else {
         ESP_LOGE(TAG, "unknown MMC CSD structure version 0x%x", out_csd->csd_ver);
-        return 1;
+        return ESP_ERR_NOT_SUPPORTED;
     }
     int read_bl_size = 1 << out_csd->read_block_len;
     out_csd->sector_size = MIN(read_bl_size, 512);
@@ -292,7 +292,7 @@ esp_err_t sdmmc_init_mmc_check_ext_csd(sdmmc_card_t* card)
     }
 
 out:
-    free(ext_csd);
+    heap_caps_free(ext_csd);
     return err;
 }
 
diff --git a/components/sdmmc/sdmmc_sd.c b/components/sdmmc/sdmmc_sd.c
index a66b535bb74..dc4019dd6b9 100644
--- a/components/sdmmc/sdmmc_sd.c
+++ b/components/sdmmc/sdmmc_sd.c
@@ -120,7 +120,7 @@ esp_err_t sdmmc_init_sd_ssr(sdmmc_card_t* card)
     // read SD status register
     err = sdmmc_send_app_cmd(card, &cmd);
     if (err != ESP_OK) {
-        free(sd_ssr);
+        heap_caps_free(sd_ssr);
         ESP_LOGE(TAG, "%s: sdmmc_send_cmd returned 0x%x", __func__, err);
         return err;
     }
@@ -129,7 +129,7 @@ esp_err_t sdmmc_init_sd_ssr(sdmmc_card_t* card)
     if (err != ESP_OK) {
         ESP_LOGE(TAG, "%s: error sdmmc_decode_ssr returned 0x%x", __func__, err);
     }
-    free(sd_ssr);
+    heap_caps_free(sd_ssr);
     return err;
 }
 
@@ -320,7 +320,7 @@ esp_err_t sdmmc_enter_higher_speed_mode(sdmmc_card_t* card)
     }
 
 out:
-    free(response);
+    heap_caps_free(response);
     return err;
 }
 
@@ -515,7 +515,7 @@ esp_err_t sdmmc_select_driver_strength(sdmmc_card_t *card, sdmmc_driver_strength
     ESP_GOTO_ON_FALSE(supported_mask == driver_strength, ESP_ERR_INVALID_ARG, out, TAG, "fail to switch to type 0x%x", driver_strength);
 
 out:
-    free(response);
+    heap_caps_free(response);
     return ret;
 }
 
@@ -622,7 +622,7 @@ esp_err_t sdmmc_select_current_limit(sdmmc_card_t *card, sdmmc_current_limit_t c
     ESP_GOTO_ON_FALSE(supported_mask == current_limit, ESP_ERR_INVALID_ARG, out, TAG, "fail to switch to type 0x%x", current_limit);
 
 out:
-    free(response);
+    heap_caps_free(response);
     return ret;
 }