fix: skip data flash usage scan in status command

Data flash reads undefined values after erase (not 0xFF) per Renesas
RA4M2 manual section 44.16.2 ?!. So usage cannot be reliably
determined. Display "usage unknown" instead of misleading percentages.

Signed-off-by: Vincent Jardin <vjardin@free.fr>

Author: vjardin

src/radfu.c

@@ -3166,7 +3166,7 @@ ra_status(ra_device_t *dev) {
 
   /* Calculate memory sizes and usage */
   uint32_t code_size = 0, code_used = 0;
-  uint32_t data_size = 0, data_used = 0;
+  uint32_t data_size = 0;
   uint32_t config_size = 0;
   uint32_t code_sad = 0, code_ead = 0;
   uint32_t data_sad = 0, data_ead = 0;
@@ -3212,17 +3212,9 @@ ra_status(ra_device_t *dev) {
     }
   }
 
-  if (data_size > 0 && dev->chip_layout[1].rau != 0) {
-    fprintf(stderr, "Scanning data flash usage...\n");
-    for (int i = 0; i < MAX_AREAS; i++) {
-      ra_area_t *area = &dev->chip_layout[i];
-      if (area->koa == KOA_TYPE_DATA && area->ead != 0 && area->rau != 0) {
-        int64_t used = status_scan_flash_usage(dev, area->sad, area->ead, area->rau);
-        if (used >= 0)
-          data_used += (uint32_t)used;
-      }
-    }
-  }
+  /* NOTE: Data flash usage scanning is skipped because erased data flash
+   * reads undefined values (not 0xFF) per Renesas RA hardware spec.
+   * The bootloader protocol does not expose a reliable blank-check method. */
 
   /* Print status display */
   printf("\n");
@@ -3372,18 +3364,12 @@ ra_status(ra_device_t *dev) {
       status_print_line(line, STATUS_WIDTH);
     }
 
-    /* Data Flash - usage bar */
-    pct = (data_size > 0) ? (int)((uint64_t)data_used * 100 / data_size) : 0;
-    int df_filled = (data_size > 0) ? (int)((uint64_t)data_used * 40 / data_size) : 0;
-    if (df_filled > 40)
-      df_filled = 40;
-    bar_buf[0] = '\0';
-    strcat(bar_buf, " ");
-    for (int i = 0; i < df_filled; i++)
-      strcat(bar_buf, BAR_FULL);
-    for (int i = df_filled; i < 40; i++)
-      strcat(bar_buf, BAR_EMPTY);
-    snprintf(content, sizeof(content), "%s  %3d%% used", bar_buf, pct);
+    /* Data Flash - usage cannot be determined (hardware limitation)
+     * Per RA4M2 manual 44.16.2: "Values read from data flash memory that has
+     * been erased but not yet been programming again are undefined."
+     * The bootloader protocol does not expose the hardware blank check. */
+    snprintf(
+        content, sizeof(content), " (usage unknown - erased data reads undefined per HW spec)");
     status_format_inner(line, sizeof(line), content, INNER_WIDTH);
     status_print_line(line, STATUS_WIDTH);
   }