diff --git a/arduino/beken-72xx/cores/arduino/LibreTuyaAPI.cpp b/arduino/beken-72xx/cores/arduino/LibreTuyaAPI.cpp
index d3927a0..47faf56 100644
--- a/arduino/beken-72xx/cores/arduino/LibreTuyaAPI.cpp
+++ b/arduino/beken-72xx/cores/arduino/LibreTuyaAPI.cpp
@@ -1,6 +1,7 @@
 /* Copyright (c) Kuba Szczodrzyński 2022-06-19. */
 
 #include <LibreTuyaAPI.h>
+#include <libraries/Flash/Flash.h>
 
 // can't include <flash.h> as it collides with <Flash.h> on Windows -_-
 #define REG_FLASH_BASE		 0x00803000
@@ -109,12 +110,14 @@ uint32_t LibreTuya::getMaxAllocHeap() {
 
 /* OTA-related */
 
+static int8_t otaImage2Valid = -1;
+
 uint8_t LibreTuya::otaGetStoredIndex() {
-	return 1;
+	return otaHasImage2() ? 2 : 1;
 }
 
 bool LibreTuya::otaSupportsDual() {
-	return false;
+	return true;
 }
 
 bool LibreTuya::otaHasImage1() {
@@ -122,11 +125,28 @@ bool LibreTuya::otaHasImage1() {
 }
 
 bool LibreTuya::otaHasImage2() {
-	return false;
+	if (otaImage2Valid != -1)
+		return otaImage2Valid;
+	// check download RBL
+	// TODO: maybe check header CRC or even binary hashes
+	uint32_t magic;
+	Flash.readBlock(FLASH_DOWNLOAD_OFFSET, (uint8_t *)&magic, 4);
+	otaImage2Valid = magic == 0x004C4252; // "RBL\0", little-endian
+	return otaImage2Valid;
 }
 
 bool LibreTuya::otaSwitch(bool force) {
-	return true;
+	// no need to check otaGetStoredIndex() as it does the same as otaHasImage2()
+
+	// force checking validity again
+	otaImage2Valid = -1;
+
+	if (otaHasImage2() && force) {
+		// "rollback" - abort bootloader upgrade operation by wiping first sector
+		return Flash.eraseSector(FLASH_DOWNLOAD_OFFSET);
+	}
+
+	return otaHasImage2(); // false if second image is not valid
 }
 
 /* Global instance */
diff --git a/arduino/libretuya/core/ChipType.h b/arduino/libretuya/core/ChipType.h
index 205bd01..7d27df2 100644
--- a/arduino/libretuya/core/ChipType.h
+++ b/arduino/libretuya/core/ChipType.h
@@ -1,5 +1,7 @@
 /* Copyright (c) Kuba Szczodrzyński 2022-05-28. */
 
+#pragma once
+
 #define CHIP_TYPE(family, chip_id)		(((family >> 24) << 8) | chip_id)
 #define CHIP_TYPE_ENUM(family, chip_id) (ChipType) CHIP_TYPE(family, chip_id)
 
diff --git a/arduino/libretuya/core/LibreTuyaClass.cpp b/arduino/libretuya/core/LibreTuyaClass.cpp
index b8c446f..fb739da 100644
--- a/arduino/libretuya/core/LibreTuyaClass.cpp
+++ b/arduino/libretuya/core/LibreTuyaClass.cpp
@@ -98,7 +98,8 @@ uint8_t LibreTuya::otaGetTarget() {
 }
 
 /**
- * @brief Perform OTA rollback.
+ * @brief Perform OTA rollback: switch to the previous image, or abort current
+ * switched OTA update, if not rebooted yet.
  *
  * @return false if no second image to run, writing failed or dual-OTA not supported
  */
diff --git a/arduino/libretuya/core/LibreTuyaClass.h b/arduino/libretuya/core/LibreTuyaClass.h
index 944e9ab..82a2d33 100644
--- a/arduino/libretuya/core/LibreTuyaClass.h
+++ b/arduino/libretuya/core/LibreTuyaClass.h
@@ -114,7 +114,9 @@ class LibreTuya {
 	 */
 	uint8_t otaGetStoredIndex();
 	/**
-	 * @brief Check if the chip supports dual-OTA.
+	 * @brief Check if the chip supports dual-OTA (i.e. OTA is flashed to a different partition).
+	 *
+	 * TODO: make this work for actual dual-OTA chips; remove checking this in otaGetTarget() etc.
 	 */
 	bool otaSupportsDual();
 	/**
diff --git a/arduino/libretuya/core/LibreTuyaConfig.h b/arduino/libretuya/core/LibreTuyaConfig.h
index a445c4b..3c097a5 100644
--- a/arduino/libretuya/core/LibreTuyaConfig.h
+++ b/arduino/libretuya/core/LibreTuyaConfig.h
@@ -95,3 +95,7 @@
 #ifndef LT_DEBUG_SSL
 #define LT_DEBUG_SSL 0
 #endif
+
+#ifndef LT_DEBUG_OTA
+#define LT_DEBUG_OTA 0
+#endif
diff --git a/arduino/libretuya/core/lt_logger.h b/arduino/libretuya/core/lt_logger.h
index 84ac288..d4c4f6b 100644
--- a/arduino/libretuya/core/lt_logger.h
+++ b/arduino/libretuya/core/lt_logger.h
@@ -185,3 +185,8 @@ void lt_log_disable();
 #define LT_T_SSL(...) LT_T_MOD(LT_DEBUG_SSL, __VA_ARGS__)
 #define LT_V_SSL(...) LT_T_MOD(LT_DEBUG_SSL, __VA_ARGS__)
 #define LT_D_SSL(...) LT_D_MOD(LT_DEBUG_SSL, __VA_ARGS__)
+
+// Update.cpp
+#define LT_T_OTA(...) LT_T_MOD(LT_DEBUG_OTA, __VA_ARGS__)
+#define LT_V_OTA(...) LT_T_MOD(LT_DEBUG_OTA, __VA_ARGS__)
+#define LT_D_OTA(...) LT_D_MOD(LT_DEBUG_OTA, __VA_ARGS__)
diff --git a/arduino/libretuya/libraries/Update/Update.cpp b/arduino/libretuya/libraries/Update/Update.cpp
index 983f469..da74810 100644
--- a/arduino/libretuya/libraries/Update/Update.cpp
+++ b/arduino/libretuya/libraries/Update/Update.cpp
@@ -18,6 +18,8 @@ bool UpdateClass::begin(size_t size, int command, int unused2, uint8_t unused3,
 		return false;
 	cleanup();
 
+	LT_D_OTA("begin(%u, ...) / OTA curr: %u, trgt: %u", size, LT.otaGetRunning(), LT.otaGetTarget());
+
 	ctx	 = uf2_ctx_init(LT.otaGetTarget(), FAMILY);
 	info = uf2_info_init();
 
@@ -70,6 +72,8 @@ size_t UpdateClass::write(uint8_t *data, size_t len) {
 		// 0 if not running
 		return 0;
 
+	LT_D_OTA("write(%u) / buf %u/512", len, bufSize());
+
 	/* while (buf == bufPos && len >= UF2_BLOCK_SIZE) {
 		// buffer empty and entire block is in data
 		if (!tryWriteData(data, UF2_BLOCK_SIZE)) {
@@ -82,7 +86,7 @@ size_t UpdateClass::write(uint8_t *data, size_t len) {
 	} */
 
 	// write until buffer space is available
-	uint16_t toWrite;
+	uint16_t toWrite; // 1..512
 	while (len && (toWrite = min(len, bufLeft()))) {
 		tryWriteData(data, toWrite);
 		if (hasError())
@@ -141,6 +145,8 @@ size_t UpdateClass::writeStream(Stream &data) {
 size_t UpdateClass::tryWriteData(uint8_t *data, size_t len) {
 	uf2_block_t *block = NULL;
 
+	LT_V_OTA("Writing %u to buffer (%u/512)", len, bufSize());
+
 	if (len == UF2_BLOCK_SIZE) {
 		// data has a complete block
 		block = (uf2_block_t *)data;
@@ -172,11 +178,14 @@ size_t UpdateClass::tryWriteData(uint8_t *data, size_t len) {
 				// header is invalid
 				return 0;
 
+			LT_I("OTA: %s v%s - LT v%s @ %s", info->fw_name, info->fw_version, info->lt_version, info->board);
+
 			if (bytesTotal == UPDATE_SIZE_UNKNOWN) {
 				// set total update size from block count info
 				bytesTotal = block->block_count * UF2_BLOCK_SIZE;
 			} else if (bytesTotal != block->block_count * UF2_BLOCK_SIZE) {
 				// given update size does not match the block count
+				LT_D_OTA("Image size wrong; got %u, calculated %u", bytesTotal, block->block_count * UF2_BLOCK_SIZE);
 				return errorArd(UPDATE_ERROR_SIZE);
 			}
 		} else {
diff --git a/arduino/libretuya/libraries/Update/Update.h b/arduino/libretuya/libraries/Update/Update.h
index 6c5e4ca..26211d2 100644
--- a/arduino/libretuya/libraries/Update/Update.h
+++ b/arduino/libretuya/libraries/Update/Update.h
@@ -118,7 +118,7 @@ class UpdateClass {
 	}
 
 	void clearError() {
-		errorUf2(UF2_ERR_OK);
+		errorArd(UPDATE_ERROR_OK);
 	}
 
 	bool hasError() {
diff --git a/arduino/libretuya/libraries/Update/UpdateUtil.cpp b/arduino/libretuya/libraries/Update/UpdateUtil.cpp
index e5f1c0e..d9d8b76 100644
--- a/arduino/libretuya/libraries/Update/UpdateUtil.cpp
+++ b/arduino/libretuya/libraries/Update/UpdateUtil.cpp
@@ -52,6 +52,8 @@ void UpdateClass::cleanup() {
  * @return true if err is not OK, false otherwise
  */
 bool UpdateClass::errorUf2(uf2_err_t err) {
+	if (err)
+		LT_D_OTA("[%4d] errorUf2(%d)", ctx ? ctx->seq : 0, err);
 	if (err <= UF2_ERR_IGNORE)
 		return false;
 	cleanup();
@@ -67,6 +69,8 @@ bool UpdateClass::errorUf2(uf2_err_t err) {
  * @return false - always
  */
 bool UpdateClass::errorArd(uint8_t err) {
+	if (err)
+		LT_D_OTA("[%4d] errorArd(%d)", ctx ? ctx->seq : 0, err);
 	cleanup();
 	errUf2 = UF2_ERR_OK;
 	errArd = err;
@@ -77,6 +81,7 @@ bool UpdateClass::errorArd(uint8_t err) {
  * @brief Abort the update with UPDATE_ERROR_ABORT reason.
  */
 void UpdateClass::abort() {
+	LT_D_OTA("Aborting update");
 	errorArd(UPDATE_ERROR_ABORT);
 }
 
@@ -105,7 +110,7 @@ void UpdateClass::printError(Print &out) {
  * "ard=..,uf2=..". Returns "" if no error.
  */
 const char *UpdateClass::errorString() {
-	if (!errArd)
+	if (!errArd && !errUf2)
 		return "";
 	sprintf(errorStr, "ard=%u,uf2=%u", errArd, errUf2);
 	return errorStr;