PYFW-378: Make possible to downgrade from 1.20 to 1.18.3

Author: husigeza

esp32/ftp/updater.c

@@ -148,81 +148,87 @@ bool updater_start (void) {
 
     esp_err_t ret;
 
-    // Save the current OTADATA partition before updating the partition table
+    // Get the current otadata partition
     boot_info_t boot_info_local;
     uint32_t boot_info_offset_local;
     if(true != updater_read_boot_info(&boot_info_local, &boot_info_offset_local)) {
         ESP_LOGE(TAG, "Reading boot info (otadata partition) failed!\n");
         return false;
     }
 
-    // Erasing address space of bootloader in 4 KB chunks, it is from 0x1000-0x9000 = 32KB (SPI_FLASH_SEC_SIZE = 4KB)
-    for(int i = 0; i < 8; i++){
-        ret = spi_flash_erase_sector((0x1000 + (i*SPI_FLASH_SEC_SIZE)) / SPI_FLASH_SEC_SIZE);
+    // Only update bootloader, otadata and partition table if coming from older version (e.g. 1.18.2) and this is not a downgrade
+    // In case of upgrade the boot_info located under 0x190000 address
+    // In case of a downgrade, the boot info located somewhere else than 0x190000 because of the updated partition table
+    if(boot_info_offset_local == (uint32_t)0x190000){
+
+        // Erasing address space of bootloader in 4 KB chunks, it is from 0x1000-0x9000 = 32KB (SPI_FLASH_SEC_SIZE = 4KB)
+        for(int i = 0; i < 8; i++){
+            ret = spi_flash_erase_sector((0x1000 + (i*SPI_FLASH_SEC_SIZE)) / SPI_FLASH_SEC_SIZE);
+            if (ESP_OK != ret) {
+                ESP_LOGE(TAG, "Erasing sectors of bootloader failed, error code: %d!\n", ret);
+                // TODO: try again ???
+                return false;
+            }
+        }
+
+        // Update bootloader
+        ret = spi_flash_write(0x1000, (void *)bootloader_bin, sizeof(bootloader_bin));
         if (ESP_OK != ret) {
-            ESP_LOGE(TAG, "Erasing sectors of bootloader failed, error code: %d!\n", ret);
-            // TODO: try again ???
+            ESP_LOGE(TAG, "Updating bootloader failed, error code: %d\n", ret);
+            //TODO: try again ???
             return false;
         }
-    }
 
-    // Update bootloader
-    ret = spi_flash_write(0x1000, (void *)bootloader_bin, sizeof(bootloader_bin));
-    if (ESP_OK != ret) {
-        ESP_LOGE(TAG, "Updating bootloader failed, error code: %d\n", ret);
-        //TODO: try again ???
-        return false;
-    }
-
-    /* Erasing the NEW location of otadata partition, this will ruin/corrupt the current firmware on "ota_0" partition
-     * The new location of otadata is 0x1BE000 or 0x1FF000 as per updated partition table and has size of
-     * 4096 bytes which is size of a sector
-     */
-    if (esp32_get_chip_rev() > 0) {
-        ret = spi_flash_erase_sector(OTA_DATA_ADDRESS_8MB / SPI_FLASH_SEC_SIZE);
-    }
-    else {
-        ret = spi_flash_erase_sector(OTA_DATA_ADDRESS_4MB / SPI_FLASH_SEC_SIZE);
-    }
-    if (ESP_OK != ret) {
-        ESP_LOGE(TAG, "Erasing new sector of boot info failed, error code: %d!\n", ret);
-        // TODO: try again ???
-        return false;
-    }
+        /* Erasing the NEW location of otadata partition, this will ruin/corrupt the current firmware on "ota_0" partition
+         * The new location of otadata is 0x1BE000 or 0x1FF000 as per updated partition table and has size of
+         * 4096 bytes which is size of a sector
+         */
+        if (esp32_get_chip_rev() > 0) {
+            ret = spi_flash_erase_sector(OTA_DATA_ADDRESS_8MB / SPI_FLASH_SEC_SIZE);
+        }
+        else {
+            ret = spi_flash_erase_sector(OTA_DATA_ADDRESS_4MB / SPI_FLASH_SEC_SIZE);
+        }
+        if (ESP_OK != ret) {
+            ESP_LOGE(TAG, "Erasing new sector of boot info failed, error code: %d!\n", ret);
+            // TODO: try again ???
+            return false;
+        }
 
-    // Updating the NEW otadata partition with the OLD information
-    bool updater_ret = false;
-    if (esp32_get_chip_rev() > 0) {
-        updater_ret = updater_write_boot_info(&boot_info_local, OTA_DATA_ADDRESS_8MB);
-    }
-    else {
-        updater_ret = updater_write_boot_info(&boot_info_local, OTA_DATA_ADDRESS_4MB);
-    }
-    if (true != updater_ret) {
-        ESP_LOGE(TAG, "Writing new sector of boot info failed!\n");
-        //TODO: try again ???
-        return false;
-    }
+        // Updating the NEW otadata partition with the OLD information
+        bool updater_ret = false;
+        if (esp32_get_chip_rev() > 0) {
+            updater_ret = updater_write_boot_info(&boot_info_local, OTA_DATA_ADDRESS_8MB);
+        }
+        else {
+            updater_ret = updater_write_boot_info(&boot_info_local, OTA_DATA_ADDRESS_4MB);
+        }
+        if (true != updater_ret) {
+            ESP_LOGE(TAG, "Writing new sector of boot info failed!\n");
+            //TODO: try again ???
+            return false;
+        }
 
-    // Update partition table, it has size of 4096 which is 1 sector
-    ret = spi_flash_erase_sector(ESP_PARTITION_TABLE_ADDR / SPI_FLASH_SEC_SIZE);
-    if (ESP_OK != ret) {
-        ESP_LOGE(TAG, "Erasing partition table partition failed, error code: %d!\n", ret);
-        //TODO: write back old one ??
-        return false;
-    }
+        // Update partition table, it has size of 4096 which is 1 sector
+        ret = spi_flash_erase_sector(ESP_PARTITION_TABLE_ADDR / SPI_FLASH_SEC_SIZE);
+        if (ESP_OK != ret) {
+            ESP_LOGE(TAG, "Erasing partition table partition failed, error code: %d!\n", ret);
+            //TODO: write back old one ??
+            return false;
+        }
 
-    // Writing the new partition table
-    if (esp32_get_chip_rev() > 0) {
-        ret = spi_flash_write(ESP_PARTITION_TABLE_ADDR, (void *)partitions_bin_8MB, sizeof(partitions_bin_8MB));
-    }
-    else {
-        ret = spi_flash_write(ESP_PARTITION_TABLE_ADDR, (void *)partitions_bin_4MB, sizeof(partitions_bin_4MB));
-    }
-    if (ESP_OK != ret) {
-        ESP_LOGE(TAG, "Writing new partition table failed, error code: %d\n", ret);
-        //TODO: try again ???
-        return false;
+        // Writing the new partition table
+        if (esp32_get_chip_rev() > 0) {
+            ret = spi_flash_write(ESP_PARTITION_TABLE_ADDR, (void *)partitions_bin_8MB, sizeof(partitions_bin_8MB));
+        }
+        else {
+            ret = spi_flash_write(ESP_PARTITION_TABLE_ADDR, (void *)partitions_bin_4MB, sizeof(partitions_bin_4MB));
+        }
+        if (ESP_OK != ret) {
+            ESP_LOGE(TAG, "Writing new partition table failed, error code: %d\n", ret);
+            //TODO: try again ???
+            return false;
+        }
     }
 
     updater_data.size = (esp32_get_chip_rev() > 0 ? IMG_SIZE_8MB : IMG_SIZE_4MB);

esp32/mptask.c

@@ -144,14 +144,19 @@ void TASK_Micropython (void *pvParameters) {
         ret = updater_read_boot_info(&boot_info_local, &boot_info_offset_local);
     }
     if(boot_info_local.ActiveImg != IMG_ACT_FACTORY) {
-        printf("Copying image from OTA_0 partition to Factory partition, please wait...\n");
-        if(true == update_to_factory_partition()) {
-            printf("Image copy finished successfully!\n");
-        }
+        // Only copy if coming from older version (1.18.2) and this is not a downgrade
+        // In case of upgrade the boot_info located under 0x190000 address
+        // In case of a downgrade, the boot info located somewhere else than 0x190000 because of the updated partition table
+        if(boot_info_offset_local == (uint32_t)0x190000){
+            printf("Copying image from OTA_0 partition to Factory partition, please wait...\n");
+            if(true == update_to_factory_partition()) {
+                printf("Image copy finished successfully!\n");
+            }
 
-        //Restart the system
-        machine_wdt_start(100);
-        for ( ; ; );
+            //Restart the system
+            machine_wdt_start(100);
+            for ( ; ; );
+        }
     }
 
     // configure the antenna select switch here