diff --git a/src/common/crypto/Algorithm.cpp b/src/common/crypto/Algorithm.cpp
index 909c772ab..2f2593726 100644
--- a/src/common/crypto/Algorithm.cpp
+++ b/src/common/crypto/Algorithm.cpp
@@ -150,10 +150,16 @@ void xmrig::Algorithm::parseAlgorithm(const char *algo)
     m_variant = VARIANT_AUTO;
 
     assert(algo != nullptr);
-    if (algo == nullptr) {
+    if (algo == nullptr || strlen(algo) < 1) {
         return;
     }
 
+    if (*algo == '!') {
+        m_flags |= Forced;
+
+        return parseAlgorithm(algo + 1);
+    }
+
     for (size_t i = 0; i < ARRAY_SIZE(algorithms); i++) {
         if ((strcasecmp(algo, algorithms[i].name) == 0) || (strcasecmp(algo, algorithms[i].shortName) == 0)) {
             m_algo    = algorithms[i].algo;
@@ -172,6 +178,16 @@ void xmrig::Algorithm::parseVariant(const char *variant)
 {
     m_variant = VARIANT_AUTO;
 
+    if (variant == nullptr || strlen(variant) < 1) {
+        return;
+    }
+
+    if (*variant == '!') {
+        m_flags |= Forced;
+
+        return parseVariant(variant + 1);
+    }
+
     for (size_t i = 0; i < ARRAY_SIZE(variants); i++) {
         if (strcasecmp(variant, variants[i]) == 0) {
             m_variant = static_cast<Variant>(i);
diff --git a/src/common/crypto/Algorithm.h b/src/common/crypto/Algorithm.h
index 4a975ad1e..f4380d45f 100644
--- a/src/common/crypto/Algorithm.h
+++ b/src/common/crypto/Algorithm.h
@@ -39,28 +39,38 @@ namespace xmrig {
 class Algorithm
 {
 public:
+    enum Flags {
+        None   = 0,
+        Forced = 1
+    };
+
     inline Algorithm() :
         m_algo(INVALID_ALGO),
+        m_flags(0),
         m_variant(VARIANT_AUTO)
     {}
 
     inline Algorithm(Algo algo, Variant variant) :
+        m_flags(0),
         m_variant(variant)
     {
         setAlgo(algo);
     }
 
-    inline Algorithm(const char *algo)
+    inline Algorithm(const char *algo) :
+        m_flags(0)
     {
         parseAlgorithm(algo);
     }
 
-    bool isEqual(const Algorithm &other) const { return m_algo == other.m_algo && m_variant == other.m_variant; }
-    inline Algo algo() const                   { return m_algo; }
-    inline const char *name() const            { return name(false); }
-    inline const char *shortName() const       { return name(true); }
-    inline Variant variant() const             { return m_variant; }
-    inline void setVariant(Variant variant)    { m_variant = variant; }
+    inline Algo algo() const                          { return m_algo; }
+    inline bool isEqual(const Algorithm &other) const { return m_algo == other.m_algo && m_variant == other.m_variant; }
+    inline bool isForced() const                      { return m_flags & Forced; }
+    inline const char *name() const                   { return name(false); }
+    inline const char *shortName() const              { return name(true); }
+    inline int flags() const                          { return m_flags; }
+    inline Variant variant() const                    { return m_variant; }
+    inline void setVariant(Variant variant)           { m_variant = variant; }
 
     inline bool operator!=(const Algorithm &other) const  { return !isEqual(other); }
     inline bool operator==(const Algorithm &other) const  { return isEqual(other); }
@@ -80,6 +90,7 @@ private:
     const char *name(bool shortName) const;
 
     Algo m_algo;
+    int m_flags;
     Variant m_variant;
 };
 
diff --git a/src/common/net/Job.cpp b/src/common/net/Job.cpp
index 2eb84f187..7da2ed83b 100644
--- a/src/common/net/Job.cpp
+++ b/src/common/net/Job.cpp
@@ -124,11 +124,14 @@ bool Job::setBlob(const char *blob)
     if (m_autoVariant) {
         m_algorithm.setVariant(variant());
     }
-    else if (m_algorithm.variant() == xmrig::VARIANT_XTL && m_blob[0] >= 9) {
-        m_algorithm.setVariant(xmrig::VARIANT_HALF);
-    }
-    else if (m_algorithm.variant() == xmrig::VARIANT_MSR && m_blob[0] >= 8) {
-        m_algorithm.setVariant(xmrig::VARIANT_HALF);
+
+    if (!m_algorithm.isForced()) {
+        if (m_algorithm.variant() == xmrig::VARIANT_XTL && m_blob[0] >= 9) {
+            m_algorithm.setVariant(xmrig::VARIANT_HALF);
+        }
+        else if (m_algorithm.variant() == xmrig::VARIANT_MSR && m_blob[0] >= 8) {
+            m_algorithm.setVariant(xmrig::VARIANT_HALF);
+        }
     }
 
 #   ifdef XMRIG_PROXY_PROJECT