diff --git a/src/p2pool.cpp b/src/p2pool.cpp
index eb76f73..ff61887 100644
--- a/src/p2pool.cpp
+++ b/src/p2pool.cpp
@@ -219,9 +219,9 @@ p2pool::~p2pool()
 	delete m_params;
 }
 
-bool p2pool::calculate_hash(const void* data, size_t size, uint64_t height, const hash& seed, hash& result)
+bool p2pool::calculate_hash(const void* data, size_t size, uint64_t height, const hash& seed, hash& result, bool force_light_mode)
 {
-	return m_hasher->calculate(data, size, height, seed, result);
+	return m_hasher->calculate(data, size, height, seed, result, force_light_mode);
 }
 
 uint64_t p2pool::get_seed_height(uint64_t height)
diff --git a/src/p2pool.h b/src/p2pool.h
index 38d2590..bfc1337 100644
--- a/src/p2pool.h
+++ b/src/p2pool.h
@@ -60,7 +60,7 @@ public:
 	p2pool_api* api() const { return m_api; }
 
 	RandomX_Hasher_Base* hasher() const { return m_hasher; }
-	bool calculate_hash(const void* data, size_t size, uint64_t height, const hash& seed, hash& result);
+	bool calculate_hash(const void* data, size_t size, uint64_t height, const hash& seed, hash& result, bool force_light_mode);
 	static uint64_t get_seed_height(uint64_t height);
 	bool get_seed(uint64_t height, hash& seed) const;
 
diff --git a/src/pool_block.cpp b/src/pool_block.cpp
index f76fa4a..6e9b051 100644
--- a/src/pool_block.cpp
+++ b/src/pool_block.cpp
@@ -271,7 +271,7 @@ void PoolBlock::reset_offchain_data()
 	m_receivedTimestamp = 0;
 }
 
-bool PoolBlock::get_pow_hash(RandomX_Hasher_Base* hasher, uint64_t height, const hash& seed_hash, hash& pow_hash)
+bool PoolBlock::get_pow_hash(RandomX_Hasher_Base* hasher, uint64_t height, const hash& seed_hash, hash& pow_hash, bool force_light_mode)
 {
 	alignas(8) uint8_t hashes[HASH_SIZE * 3];
 
@@ -349,7 +349,7 @@ bool PoolBlock::get_pow_hash(RandomX_Hasher_Base* hasher, uint64_t height, const
 
 	writeVarint(count, [&blob, &blob_size](uint8_t b) { blob[blob_size++] = b; });
 
-	return hasher->calculate(blob, blob_size, height, seed_hash, pow_hash);
+	return hasher->calculate(blob, blob_size, height, seed_hash, pow_hash, force_light_mode);
 }
 
 uint64_t PoolBlock::get_payout(const Wallet& w) const
diff --git a/src/pool_block.h b/src/pool_block.h
index 793798f..49f2b25 100644
--- a/src/pool_block.h
+++ b/src/pool_block.h
@@ -141,7 +141,7 @@ struct PoolBlock
 	int deserialize(const uint8_t* data, size_t size, const SideChain& sidechain, uv_loop_t* loop, bool compact);
 	void reset_offchain_data();
 
-	bool get_pow_hash(RandomX_Hasher_Base* hasher, uint64_t height, const hash& seed_hash, hash& pow_hash);
+	bool get_pow_hash(RandomX_Hasher_Base* hasher, uint64_t height, const hash& seed_hash, hash& pow_hash, bool force_light_mode = false);
 
 	uint64_t get_payout(const Wallet& w) const;
 
diff --git a/src/pow_hash.cpp b/src/pow_hash.cpp
index 4713577..4afe46f 100644
--- a/src/pow_hash.cpp
+++ b/src/pow_hash.cpp
@@ -322,10 +322,10 @@ void RandomX_Hasher::sync_wait()
 	ReadLock lock2(m_cacheLock);
 }
 
-bool RandomX_Hasher::calculate(const void* data, size_t size, uint64_t /*height*/, const hash& seed, hash& result)
+bool RandomX_Hasher::calculate(const void* data, size_t size, uint64_t /*height*/, const hash& seed, hash& result, bool force_light_mode)
 {
 	// First try to use the dataset if it's ready
-	if (uv_rwlock_tryrdlock(&m_datasetLock) == 0) {
+	if (!force_light_mode && (uv_rwlock_tryrdlock(&m_datasetLock) == 0)) {
 		ON_SCOPE_LEAVE([this]() { uv_rwlock_rdunlock(&m_datasetLock); });
 
 		if (m_stopped.load()) {
@@ -340,7 +340,7 @@ bool RandomX_Hasher::calculate(const void* data, size_t size, uint64_t /*height*
 		}
 	}
 
-	// If dataset is not ready, use the cache and wait if necessary
+	// If dataset is not ready, or force_light_mode = true, use the cache and wait if necessary
 	ReadLock lock(m_cacheLock);
 
 	if (m_stopped.load()) {
@@ -429,7 +429,7 @@ void RandomX_Hasher_RPC::loop(void* data)
 	LOGINFO(1, "event loop stopped");
 }
 
-bool RandomX_Hasher_RPC::calculate(const void* data_ptr, size_t size, uint64_t height, const hash& /*seed*/, hash& h)
+bool RandomX_Hasher_RPC::calculate(const void* data_ptr, size_t size, uint64_t height, const hash& /*seed*/, hash& h, bool /*force_light_mode*/)
 {
 	MutexLock lock(m_requestMutex);
 
diff --git a/src/pow_hash.h b/src/pow_hash.h
index ff040b2..104adad 100644
--- a/src/pow_hash.h
+++ b/src/pow_hash.h
@@ -40,7 +40,7 @@ public:
 	virtual uint32_t seed_counter() const { return 0; }
 	virtual void sync_wait() {}
 
-	virtual bool calculate(const void* data, size_t size, uint64_t height, const hash& seed, hash& result) = 0;
+	virtual bool calculate(const void* data, size_t size, uint64_t height, const hash& seed, hash& result, bool force_light_mode) = 0;
 };
 
 #ifdef WITH_RANDOMX
@@ -60,7 +60,7 @@ public:
 	uint32_t seed_counter() const override { return m_seedCounter.load(); }
 	void sync_wait() override;
 
-	bool calculate(const void* data, size_t size, uint64_t height, const hash& seed, hash& result) override;
+	bool calculate(const void* data, size_t size, uint64_t height, const hash& seed, hash& result, bool force_light_mode) override;
 
 private:
 
@@ -100,7 +100,7 @@ public:
 	explicit RandomX_Hasher_RPC(p2pool* pool);
 	~RandomX_Hasher_RPC();
 
-	bool calculate(const void* data_ptr, size_t size, uint64_t height, const hash& seed, hash& h) override;
+	bool calculate(const void* data_ptr, size_t size, uint64_t height, const hash& seed, hash& h, bool force_light_mode) override;
 
 private:
 	static void loop(void* data);
diff --git a/src/side_chain.cpp b/src/side_chain.cpp
index 2a2a2dc..1b25bea 100644
--- a/src/side_chain.cpp
+++ b/src/side_chain.cpp
@@ -570,7 +570,20 @@ bool SideChain::add_external_block(PoolBlock& block, std::vector<hash>& missing_
 	}
 
 	if (!block.m_difficulty.check_pow(pow_hash)) {
-		LOGWARN(3, "add_external_block mined by " << block.m_minerWallet << ": not enough PoW for height = " << block.m_sidechainHeight << ", mainchain height " << block.m_txinGenHeight);
+		LOGWARN(3,
+			"add_external_block mined by " << block.m_minerWallet <<
+			": not enough PoW for height = " << block.m_sidechainHeight <<
+			", id = " << block.m_sidechainId <<
+			", nonce = " << block.m_nonce <<
+			", mainchain height = " << block.m_txinGenHeight
+		);
+
+		// Calculate the same hash second time to check if it's an unstable hardware that caused this
+		hash pow_hash2;
+		if (block.get_pow_hash(m_pool->hasher(), block.m_txinGenHeight, seed, pow_hash2, true) && (pow_hash2 != pow_hash)) {
+			LOGERR(0, "UNSTABLE HARDWARE DETECTED: Calculated the same hash twice, got different results: " << pow_hash << " != " << pow_hash2 << " (sidechain id = " << block.m_sidechainId << ')');
+		}
+
 		return false;
 	}
 
diff --git a/src/stratum_server.cpp b/src/stratum_server.cpp
index 293f349..a3d6c82 100644
--- a/src/stratum_server.cpp
+++ b/src/stratum_server.cpp
@@ -881,7 +881,7 @@ void StratumServer::on_share_found(uv_work_t* req)
 		}
 
 		hash pow_hash;
-		if (!pool->calculate_hash(blob, blob_size, height, seed_hash, pow_hash)) {
+		if (!pool->calculate_hash(blob, blob_size, height, seed_hash, pow_hash, false)) {
 			LOGWARN(3, "client " << static_cast<char*>(client->m_addrString) << " couldn't check share PoW");
 			share->m_result = SubmittedShare::Result::COULDNT_CHECK_POW;
 			return;
@@ -891,6 +891,13 @@ void StratumServer::on_share_found(uv_work_t* req)
 			LOGWARN(4, "client " << static_cast<char*>(client->m_addrString) << " submitted a share with invalid PoW");
 			share->m_result = SubmittedShare::Result::INVALID_POW;
 			share->m_score = BAD_SHARE_POINTS;
+
+			// Calculate the same hash second time to check if it's an unstable hardware that caused this
+			hash pow_hash2;
+			if (pool->calculate_hash(blob, blob_size, height, seed_hash, pow_hash2, true) && (pow_hash2 != pow_hash)) {
+				LOGERR(0, "UNSTABLE HARDWARE DETECTED: Calculated the same hash twice, got different results: " << pow_hash << " != " << pow_hash2);
+			}
+
 			return;
 		}
 
diff --git a/tests/src/pool_block_tests.cpp b/tests/src/pool_block_tests.cpp
index 66b2db3..2b76386 100644
--- a/tests/src/pool_block_tests.cpp
+++ b/tests/src/pool_block_tests.cpp
@@ -87,7 +87,7 @@ TEST(pool_block, deserialize)
 	class RandomX_Hasher_Test : public RandomX_Hasher_Base
 	{
 	public:
-		bool calculate(const void* data, size_t size, uint64_t, const hash&, hash& result) override
+		bool calculate(const void* data, size_t size, uint64_t, const hash&, hash& result, bool force_light_mode) override
 		{
 			if (size == 76) {
 				char buf[76 * 2 + 1];