diff --git a/src/ast/rewriter/pb2bv_rewriter.cpp b/src/ast/rewriter/pb2bv_rewriter.cpp
index b402aeb41..fd9f5e59f 100644
--- a/src/ast/rewriter/pb2bv_rewriter.cpp
+++ b/src/ast/rewriter/pb2bv_rewriter.cpp
@@ -26,6 +26,7 @@ Notes:
 #include"ast_pp.h"
 #include"lbool.h"
 #include"uint_set.h"
+#include"gparams.h"
 
 const unsigned g_primes[7] = { 2, 3, 5, 7, 11, 13, 17};
 
@@ -819,7 +820,9 @@ struct pb2bv_rewriter::imp {
         return 
             p.get_bool("keep_cardinality_constraints", false) ||
             p.get_bool("sat.cardinality.solver", false) ||
-            p.get_bool("cardinality.solver", false) || keep_pb();
+            p.get_bool("cardinality.solver", false) || 
+            gparams::get_module("sat").get_bool("cardinality.solver", false) ||
+            keep_pb();
     }
 
     bool keep_pb() const {
@@ -827,7 +830,8 @@ struct pb2bv_rewriter::imp {
         return 
             p.get_bool("keep_pb_constraints", false) ||
             p.get_bool("sat.pb.solver", false) ||
-            p.get_bool("pb.solver", false);
+            p.get_bool("pb.solver", false) ||
+            gparams::get_module("sat").get_bool("pb.solver", false);
     }
 
     bool pb_num_system() const {
diff --git a/src/sat/card_extension.cpp b/src/sat/card_extension.cpp
index c328a30cd..5032da6ff 100644
--- a/src/sat/card_extension.cpp
+++ b/src/sat/card_extension.cpp
@@ -1025,7 +1025,6 @@ namespace sat {
 
         m_lemma.reset();        
 
-#if 1
         m_lemma.push_back(null_literal);
         for (unsigned i = 0; 0 <= slack && i < m_active_vars.size(); ++i) { 
             bool_var v = m_active_vars[i];
@@ -1048,6 +1047,7 @@ namespace sat {
             }
         }
 
+#if 0
         if (jus.size() > 1) {
             std::cout << jus.size() << "\n";
             for (unsigned i = 0; i < jus.size(); ++i) {
@@ -1057,6 +1057,7 @@ namespace sat {
             active2pb(m_A);
             display(std::cout, m_A);
         }
+#endif
 
 
         if (slack >= 0) {
@@ -1067,7 +1068,7 @@ namespace sat {
         if (m_lemma[0] == null_literal) {
             m_lemma[0] = m_lemma.back();
             m_lemma.pop_back();
-            unsigned level = lvl(m_lemma[0]);
+            unsigned level = m_lemma.empty() ? 0 : lvl(m_lemma[0]);
             for (unsigned i = 1; i < m_lemma.size(); ++i) {
                 if (lvl(m_lemma[i]) > level) {
                     level = lvl(m_lemma[i]);
@@ -1076,37 +1077,6 @@ namespace sat {
             }
             IF_VERBOSE(2, verbose_stream() << "(sat.card set level to " << level << " < " << m_conflict_lvl << ")\n";);
         }        
-#else
-        ++idx;
-        while (0 <= slack) {            
-            literal lit = lits[idx];
-            bool_var v = lit.var();
-            if (m_active_var_set.contains(v)) {
-                int coeff = get_coeff(v);
-                if (coeff < 0 && !lit.sign()) {
-                    slack += coeff;
-                    m_lemma.push_back(~lit);
-                }
-                else if (coeff > 0 && lit.sign()) {
-                    slack -= coeff;
-                    m_lemma.push_back(~lit);
-                }
-            }
-            if (idx == 0 && slack >= 0) {
-                IF_VERBOSE(2, verbose_stream() << "(sat.card non-asserting)\n";);
-                goto bail_out;
-            }
-            SASSERT(idx > 0 || slack < 0);
-            --idx;
-        }
-        if (m_lemma.size() >= 2 && lvl(m_lemma[1]) == m_conflict_lvl) {
-            // TRACE("sat", tout << "Bail out on no progress " << lit << "\n";);
-            IF_VERBOSE(2, verbose_stream() << "(sat.card bail non-asserting resolvent)\n";);
-            goto bail_out;
-        }
-
-#endif
-
 
         SASSERT(slack < 0);
 
@@ -1118,7 +1088,7 @@ namespace sat {
             svector<drat::premise> ps; // TBD fill in
             s().m_drat.add(m_lemma, ps);
         }
-        
+
         s().m_lemma.reset();
         s().m_lemma.append(m_lemma);
         for (unsigned i = 1; i < m_lemma.size(); ++i) {
diff --git a/src/sat/sat_solver.cpp b/src/sat/sat_solver.cpp
index a292ff202..ac491d6c2 100644
--- a/src/sat/sat_solver.cpp
+++ b/src/sat/sat_solver.cpp
@@ -1937,23 +1937,25 @@ namespace sat {
     void solver::learn_lemma_and_backjump() {
         TRACE("sat_lemma", tout << "new lemma size: " << m_lemma.size() << "\n" << m_lemma << "\n";);
 
-        if (m_config.m_minimize_lemmas) {
-            minimize_lemma();
-            reset_lemma_var_marks();
-            if (m_config.m_dyn_sub_res)
-                dyn_sub_res();
-            TRACE("sat_lemma", tout << "new lemma (after minimization) size: " << m_lemma.size() << "\n" << m_lemma << "\n";);
-        }
-        else
-            reset_lemma_var_marks();
-
-        literal_vector::iterator it  = m_lemma.begin();
-        literal_vector::iterator end = m_lemma.end();
         unsigned new_scope_lvl       = 0;
-        ++it;
-        for(; it != end; ++it) {
-            bool_var var = (*it).var();
-            new_scope_lvl = std::max(new_scope_lvl, lvl(var));
+        if (!m_lemma.empty()) {
+            if (m_config.m_minimize_lemmas) {
+                minimize_lemma();
+                reset_lemma_var_marks();
+                if (m_config.m_dyn_sub_res)
+                    dyn_sub_res();
+                TRACE("sat_lemma", tout << "new lemma (after minimization) size: " << m_lemma.size() << "\n" << m_lemma << "\n";);
+            }
+            else
+                reset_lemma_var_marks();
+
+            literal_vector::iterator it  = m_lemma.begin();
+            literal_vector::iterator end = m_lemma.end();
+            ++it;
+            for(; it != end; ++it) {
+                bool_var var = (*it).var();
+                new_scope_lvl = std::max(new_scope_lvl, lvl(var));
+            }
         }
 
         unsigned glue = num_diff_levels(m_lemma.size(), m_lemma.c_ptr());
@@ -2389,6 +2391,7 @@ namespace sat {
        assigned at level 0.
     */
     void solver::minimize_lemma() {
+        SASSERT(!m_lemma.empty());
         SASSERT(m_unmark.empty());
         //m_unmark.reset();
         updt_lemma_lvl_set();