diff --git a/consensus/msgs.go b/consensus/msgs.go
index cef9886e6..f4a078e71 100644
--- a/consensus/msgs.go
+++ b/consensus/msgs.go
@@ -245,6 +245,9 @@ func (m *VoteSetMaj23Message) ValidateBasic() error {
 	if !types.IsVoteTypeValid(m.Type) {
 		return errors.New("invalid Type")
 	}
+	if m.Round < 0 {
+		return errors.New("negative Round")
+	}
 	if err := m.BlockID.ValidateBasic(); err != nil {
 		return fmt.Errorf("wrong BlockID: %v", err)
 	}
diff --git a/rpc/core/blocks.go b/rpc/core/blocks.go
index 468bf7d6a..f5ddb31c6 100644
--- a/rpc/core/blocks.go
+++ b/rpc/core/blocks.go
@@ -68,12 +68,16 @@ func filterMinMax(base, height, min, max, limit uint64) (uint64, uint64, error)
 
 	// limit min to within `limit` of max
 	// so the total number of blocks returned will be `limit`
-	min = tmmath.MaxUint64(min, max-limit+1)
+	mm := tmmath.MaxInt64(int64(min), int64(max-limit+1))
 
-	if min > max {
+	// min can be zero and we will allow it
+	if mm > int64(max) {
 		return min, max, fmt.Errorf("%w: min height %d can't be greater than max height %d",
 			ctypes.ErrInvalidRequest, min, max)
 	}
+	if mm < 0 {
+		min = 0
+	}
 	return min, max, nil
 }
 
diff --git a/rpc/core/blocks_test.go b/rpc/core/blocks_test.go
index 58a557be7..bf370050b 100644
--- a/rpc/core/blocks_test.go
+++ b/rpc/core/blocks_test.go
@@ -22,7 +22,7 @@ func TestBlockchainInfo(t *testing.T) {
 		min, max     uint64
 		base, height uint64
 		limit        uint64
-		resultLength int64
+		resultLength uint64
 		wantErr      bool
 	}{
 
@@ -48,7 +48,7 @@ func TestBlockchainInfo(t *testing.T) {
 		{1, 5, 0, 1, 10, 1, false},
 		{1, 5, 0, 10, 10, 5, false},
 		{1, 15, 0, 10, 10, 10, false},
-		{1, 15, 0, 15, 10, 10, false},
+		{1, 15, 0, 15, 10, 10, false}, //
 		{1, 15, 0, 15, 20, 15, false},
 		{1, 20, 0, 15, 20, 15, false},
 		{1, 20, 0, 20, 20, 20, false},