diff --git a/components/aes67_ota/CMakeLists.txt b/components/aes67_ota/CMakeLists.txt
index bbd897e..287ae6e 100644
--- a/components/aes67_ota/CMakeLists.txt
+++ b/components/aes67_ota/CMakeLists.txt
@@ -1,2 +1,4 @@
 idf_component_register(SRCS "aes67_ota.c"
-                       INCLUDE_DIRS "include")
+                       INCLUDE_DIRS "include"
+                       PRIV_REQUIRES aes67_web app_update bootloader_support esp_app_format
+                                     esp_http_client esp_netif esp_timer hal)
diff --git a/components/aes67_ota/Kconfig b/components/aes67_ota/Kconfig
new file mode 100644
index 0000000..bf91efe
--- /dev/null
+++ b/components/aes67_ota/Kconfig
@@ -0,0 +1,11 @@
+menu "AES67 OTA"
+
+    config AES67_OTA_SELFTEST_FORCE_FAIL
+        bool "Force the OTA self-test to fail (rollback test only)"
+        default n
+        help
+            Test builds only: the self-test always fails, so a freshly installed
+            image rolls back. Build with sdkconfig.selftest_fail in a separate
+            build directory; never enable in the normal build.
+
+endmenu
diff --git a/components/aes67_ota/aes67_ota.c b/components/aes67_ota/aes67_ota.c
index 737c486..de03cb8 100644
--- a/components/aes67_ota/aes67_ota.c
+++ b/components/aes67_ota/aes67_ota.c
@@ -1,7 +1,274 @@
 #include "aes67_ota.h"
 
-// Stub (build step 0).
-esp_err_t aes67_ota_init(void)
+#include <stdio.h>
+#include <string.h>
+
+#include "aes67_web.h"
+#include "esp_app_desc.h"
+#include "esp_app_format.h"
+#include "esp_http_client.h"
+#include "esp_log.h"
+#include "esp_netif.h"
+#include "esp_ota_ops.h"
+#include "esp_timer.h"
+#include "freertos/FreeRTOS.h"
+#include "freertos/task.h"
+#include "hal/efuse_hal.h"
+
+#define CHUNK               4096
+#define SELFTEST_TIMEOUT_S  60
+// Image header, first segment header, then the app description.
+#define DESC_OFFSET         (sizeof(esp_image_header_t) + sizeof(esp_image_segment_header_t))
+#define HEAD_LEN            (DESC_OFFSET + sizeof(esp_app_desc_t))
+
+static const char *TAG = "ota";
+
+static bool is_pending(void)
 {
+    esp_ota_img_states_t st;
+    return esp_ota_get_state_partition(esp_ota_get_running_partition(), &st) == ESP_OK &&
+           st == ESP_OTA_IMG_PENDING_VERIFY;
+}
+
+/* ----- GET /api/ota ----- */
+
+static esp_err_t ota_get(httpd_req_t *req)
+{
+    const esp_app_desc_t *app = esp_app_get_description();
+    const esp_partition_t *run = esp_ota_get_running_partition();
+    const esp_partition_t *other = esp_ota_get_next_update_partition(NULL);
+    char built[40];
+    snprintf(built, sizeof(built), "%s %s", app->date, app->time);
+
+    cJSON *o = cJSON_CreateObject();
+    cJSON_AddStringToObject(o, "version", app->version);
+    cJSON_AddStringToObject(o, "project", app->project_name);
+    cJSON_AddStringToObject(o, "build_date", built);
+    cJSON_AddStringToObject(o, "idf", app->idf_ver);
+    cJSON_AddStringToObject(o, "running", run->label);
+    esp_app_desc_t prev;
+    if (other && esp_ota_get_partition_description(other, &prev) == ESP_OK) {
+        cJSON_AddStringToObject(o, "previous", other->label);
+        cJSON_AddStringToObject(o, "previous_version", prev.version);
+    }
+    cJSON_AddBoolToObject(o, "pending_verify", is_pending());
+    cJSON_AddBoolToObject(o, "can_rollback", esp_ota_check_rollback_is_possible());
+    esp_err_t err = web_send_json(req, o);
+    cJSON_Delete(o);
+    return err;
+}
+
+/* ----- POST /api/ota ----- */
+
+// Checks on the first bytes, before anything is written to flash.
+static const char *check_head(const uint8_t *buf)
+{
+    const esp_image_header_t *h = (const esp_image_header_t *)buf;
+    const esp_app_desc_t *d = (const esp_app_desc_t *)(buf + DESC_OFFSET);
+    static char msg[96];
+
+    if (h->magic != ESP_IMAGE_HEADER_MAGIC || d->magic_word != ESP_APP_DESC_MAGIC_WORD) {
+        return "not an ESP-IDF app image";
+    }
+    if (h->chip_id != CONFIG_IDF_FIRMWARE_CHIP_ID) {
+        return "image is for a different chip";
+    }
+    if (strncmp(d->project_name, esp_app_get_description()->project_name, sizeof(d->project_name)) != 0) {
+        snprintf(msg, sizeof(msg), "wrong project '%.32s'", d->project_name);
+        return msg;
+    }
+    unsigned rev = efuse_hal_chip_revision();
+    if (rev < h->min_chip_rev_full || rev > h->max_chip_rev_full) {
+        snprintf(msg, sizeof(msg), "image supports chip rev v%u.%u-v%u.%u, this chip is v%u.%u",
+                 h->min_chip_rev_full / 100, h->min_chip_rev_full % 100,
+                 h->max_chip_rev_full / 100, h->max_chip_rev_full % 100, rev / 100, rev % 100);
+        return msg;
+    }
+    return NULL;
+}
+
+static esp_err_t reject(httpd_req_t *req, const char *msg)
+{
+    ESP_LOGW(TAG, "upload rejected: %s", msg);
+    return httpd_resp_send_err(req, HTTPD_400_BAD_REQUEST, msg);
+}
+
+static esp_err_t ota_post(httpd_req_t *req)
+{
+    const esp_partition_t *dst = esp_ota_get_next_update_partition(NULL);
+    if (!dst) {
+        return reject(req, "no OTA partition");
+    }
+    if (req->content_len < HEAD_LEN || req->content_len > dst->size) {
+        return reject(req, "image size out of range");
+    }
+    uint8_t *buf = malloc(CHUNK);
+    if (!buf) {
+        return httpd_resp_send_err(req, HTTPD_500_INTERNAL_SERVER_ERROR, "out of memory");
+    }
+
+    ESP_LOGI(TAG, "upload %u bytes to %s", (unsigned)req->content_len, dst->label);
+    esp_ota_handle_t ota = 0;
+    size_t total = 0, fill = 0;
+    const char *err_msg = NULL;
+    int64_t t0 = esp_timer_get_time();
+
+    while (total < req->content_len) {
+        int r = httpd_req_recv(req, (char *)buf + fill, CHUNK - fill);
+        if (r == HTTPD_SOCK_ERR_TIMEOUT) {
+            continue;
+        }
+        if (r <= 0) {
+            err_msg = "connection lost";
+            break;
+        }
+        fill += r;
+        total += r;
+        if (!ota) {
+            // Collect the header before deciding anything.
+            if (fill < HEAD_LEN && total < req->content_len) {
+                continue;
+            }
+            if ((err_msg = check_head(buf)) != NULL) {
+                break;
+            }
+            const esp_app_desc_t *d = (const esp_app_desc_t *)(buf + DESC_OFFSET);
+            ESP_LOGI(TAG, "image %.32s %.32s", d->project_name, d->version);
+            if (esp_ota_begin(dst, OTA_WITH_SEQUENTIAL_WRITES, &ota) != ESP_OK) {
+                err_msg = "ota begin failed";
+                break;
+            }
+        }
+        if (esp_ota_write(ota, buf, fill) != ESP_OK) {
+            err_msg = "flash write failed";
+            break;
+        }
+        fill = 0;
+    }
+    free(buf);
+
+    if (err_msg) {
+        if (ota) {
+            esp_ota_abort(ota);
+        }
+        // Rejected before the whole body was read: close instead of draining it.
+        httpd_resp_set_hdr(req, "Connection", "close");
+        return reject(req, err_msg);
+    }
+    esp_err_t err = esp_ota_end(ota);  // verifies the image (checksum/hash, chip)
+    if (err != ESP_OK) {
+        return reject(req, err == ESP_ERR_OTA_VALIDATE_FAILED ? "image verification failed" : "ota end failed");
+    }
+    if (esp_ota_set_boot_partition(dst) != ESP_OK) {
+        return httpd_resp_send_err(req, HTTPD_500_INTERNAL_SERVER_ERROR, "could not set boot partition");
+    }
+    ESP_LOGW(TAG, "installed to %s in %.1f s, rebooting", dst->label,
+             (esp_timer_get_time() - t0) / 1e6);
+    httpd_resp_sendstr(req, "ok");
+    web_reboot_later(500);
+    return ESP_OK;
+}
+
+/* ----- confirm / rollback ----- */
+
+static esp_err_t confirm_post(httpd_req_t *req)
+{
+    if (!is_pending()) {
+        return httpd_resp_send_err(req, HTTPD_400_BAD_REQUEST, "running firmware is already confirmed");
+    }
+    esp_ota_mark_app_valid_cancel_rollback();
+    ESP_LOGI(TAG, "firmware confirmed via API");
+    return httpd_resp_sendstr(req, "");
+}
+
+static void rollback_cb(void *arg)
+{
+    esp_ota_mark_app_invalid_rollback_and_reboot();
+    ESP_LOGE(TAG, "rollback failed");
+}
+
+static esp_err_t rollback_post(httpd_req_t *req)
+{
+    if (!esp_ota_check_rollback_is_possible()) {
+        return httpd_resp_send_err(req, HTTPD_400_BAD_REQUEST, "no previous firmware to roll back to");
+    }
+    ESP_LOGW(TAG, "rollback requested via API");
+    httpd_resp_sendstr(req, "");
+    const esp_timer_create_args_t args = { .callback = rollback_cb, .name = "rollback" };
+    esp_timer_handle_t t;
+    if (esp_timer_create(&args, &t) == ESP_OK) {
+        esp_timer_start_once(t, 500 * 1000);
+    }
+    return ESP_OK;
+}
+
+/* ----- Self-test after an update ----- */
+
+static bool web_answers(const esp_netif_ip_info_t *ip)
+{
+    char url[48];
+    snprintf(url, sizeof(url), "http://" IPSTR "/api/status", IP2STR(&ip->ip));
+    esp_http_client_config_t cfg = { .url = url, .timeout_ms = 3000 };
+    esp_http_client_handle_t c = esp_http_client_init(&cfg);
+    bool ok = c && esp_http_client_perform(c) == ESP_OK && esp_http_client_get_status_code(c) == 200;
+    esp_http_client_cleanup(c);
+    return ok;
+}
+
+static void selftest_task(void *arg)
+{
+    const char *fail = NULL;
+    int64_t deadline = esp_timer_get_time() + SELFTEST_TIMEOUT_S * 1000000LL;
+    esp_netif_t *netif = esp_netif_get_handle_from_ifkey("ETH_DEF");
+    bool passed = false;
+
+    while (!passed && esp_timer_get_time() < deadline) {
+        vTaskDelay(pdMS_TO_TICKS(1000));
+        esp_netif_ip_info_t ip;
+        if (!netif || esp_netif_get_ip_info(netif, &ip) != ESP_OK || !ip.ip.addr) {
+            fail = "no IP address";
+            continue;
+        }
+        if (!web_answers(&ip)) {
+            fail = "web server not answering";
+            continue;
+        }
+        passed = true;
+    }
+#if CONFIG_AES67_OTA_SELFTEST_FORCE_FAIL
+    passed = false;
+    fail = "forced failure (CONFIG_AES67_OTA_SELFTEST_FORCE_FAIL)";
+#endif
+    if (passed) {
+        esp_ota_mark_app_valid_cancel_rollback();
+        ESP_LOGI(TAG, "self-test passed, firmware confirmed");
+    } else if (is_pending()) {  // not confirmed manually in the meantime
+        ESP_LOGE(TAG, "self-test failed (%s), rolling back", fail);
+        esp_ota_mark_app_invalid_rollback_and_reboot();
+    }
+    vTaskDelete(NULL);
+}
+
+esp_err_t aes67_ota_init(void)
+{
+    static const httpd_uri_t uris[] = {
+        { .uri = "/api/ota",          .method = HTTP_GET,  .handler = ota_get },
+        { .uri = "/api/ota",          .method = HTTP_POST, .handler = ota_post },
+        { .uri = "/api/ota/confirm",  .method = HTTP_POST, .handler = confirm_post },
+        { .uri = "/api/ota/rollback", .method = HTTP_POST, .handler = rollback_post },
+    };
+    for (int i = 0; i < sizeof(uris) / sizeof(uris[0]); i++) {
+        esp_err_t err = web_register_uri(&uris[i]);
+        if (err != ESP_OK) {
+            return err;
+        }
+    }
+
+    const esp_app_desc_t *app = esp_app_get_description();
+    ESP_LOGI(TAG, "running %s from %s", app->version, esp_ota_get_running_partition()->label);
+    if (is_pending()) {
+        ESP_LOGW(TAG, "new firmware on trial: self-test (IP + web) within %d s", SELFTEST_TIMEOUT_S);
+        xTaskCreate(selftest_task, "ota_selftest", 4096, NULL, 2, NULL);
+    }
     return ESP_OK;
 }
diff --git a/components/aes67_ota/include/aes67_ota.h b/components/aes67_ota/include/aes67_ota.h
index acc3450..3c134aa 100644
--- a/components/aes67_ota/include/aes67_ota.h
+++ b/components/aes67_ota/include/aes67_ota.h
@@ -4,4 +4,6 @@
 
 #include "esp_err.h"
 
+// Registers /api/ota routes. If the running image is pending verification, starts the
+// self-test: IP address + own web server answering within 60 s, else roll back.
 esp_err_t aes67_ota_init(void);
diff --git a/components/aes67_web/aes67_web.c b/components/aes67_web/aes67_web.c
index a6bff5d..b7be0d4 100644
--- a/components/aes67_web/aes67_web.c
+++ b/components/aes67_web/aes67_web.c
@@ -80,16 +80,20 @@ static void reboot_cb(void *arg)
     esp_restart();
 }
 
+void web_reboot_later(uint32_t ms)
+{
+    const esp_timer_create_args_t args = { .callback = reboot_cb, .name = "reboot" };
+    esp_timer_handle_t t;
+    if (esp_timer_create(&args, &t) == ESP_OK) {
+        esp_timer_start_once(t, ms * 1000ULL);
+    }
+}
+
 static esp_err_t reboot_post(httpd_req_t *req)
 {
     ESP_LOGW(TAG, "reboot requested via API");
     httpd_resp_sendstr(req, "");
-    // Let the response go out before restarting.
-    const esp_timer_create_args_t args = { .callback = reboot_cb, .name = "reboot" };
-    esp_timer_handle_t t;
-    if (esp_timer_create(&args, &t) == ESP_OK) {
-        esp_timer_start_once(t, 500 * 1000);
-    }
+    web_reboot_later(500);  // let the response go out first
     return ESP_OK;
 }
 
diff --git a/components/aes67_web/include/aes67_web.h b/components/aes67_web/include/aes67_web.h
index db2ac71..9f6c8f3 100644
--- a/components/aes67_web/include/aes67_web.h
+++ b/components/aes67_web/include/aes67_web.h
@@ -16,5 +16,8 @@ esp_err_t web_register_uri(const httpd_uri_t *uri);
 // Start httpd on port 80 with the core routes (/, /api/status, /api/config, /api/reboot).
 esp_err_t aes67_web_start(void);
 
+// Restart after ms (lets an HTTP response go out first).
+void web_reboot_later(uint32_t ms);
+
 // Send a cJSON object as the response body (application/json).
 esp_err_t web_send_json(httpd_req_t *req, const cJSON *json);
diff --git a/main/CMakeLists.txt b/main/CMakeLists.txt
index 4053113..e8612d6 100644
--- a/main/CMakeLists.txt
+++ b/main/CMakeLists.txt
@@ -1,5 +1,5 @@
 idf_component_register(SRCS "main.c" "project_cfg.c"
                        INCLUDE_DIRS "."
                        REQUIRES esp_app_format esp_hw_support
-                                aes67_board aes67_health aes67_net aes67_ptp
+                                aes67_board aes67_health aes67_net aes67_ota aes67_ptp
                                 aes67_syslog aes67_tx aes67_web)
diff --git a/main/main.c b/main/main.c
index 5c617eb..989253b 100644
--- a/main/main.c
+++ b/main/main.c
@@ -1,6 +1,7 @@
 #include "aes67_board.h"
 #include "aes67_health.h"
 #include "aes67_net.h"
+#include "aes67_ota.h"
 #include "aes67_ptp.h"
 #include "aes67_syslog.h"
 #include "aes67_tx.h"
@@ -33,5 +34,6 @@ void app_main(void)
     ESP_ERROR_CHECK(aes67_tx_init());
     ESP_ERROR_CHECK(aes67_syslog_init());
     project_cfg_register();
+    ESP_ERROR_CHECK(aes67_ota_init());
     ESP_ERROR_CHECK(aes67_web_start());
 }