diff --git a/fpga/hdl/action_config.v b/fpga/hdl/action_config.v
index 2533bea2..fae508ed 100644
--- a/fpga/hdl/action_config.v
+++ b/fpga/hdl/action_config.v
@@ -91,7 +91,7 @@ module action_config
     output reg [31:0]                      nframes                  ,
     output reg [7:0]                       nmodules                 ,
     output reg [3:0]                       nstorage_cells           ,
-    output reg [3:0]                       nsummation               ,
+    output reg [5:0]                       nsummation               ,
     output wire [31:0]                     hbm_size_bytes           ,
     output reg [15:0]                      spot_finder_count_threshold,
     output reg [7:0]                       spot_finder_snr_threshold,
@@ -529,7 +529,7 @@ always @(posedge clk) begin
         nsummation <= 0;
     else if (reg_data_collection_idle) begin
         if (w_hs && waddr == `ADDR_NSUMMATION)
-            nsummation <= (s_axi_WDATA[3:0] & wmask[3:0]) | (nsummation & !wmask[3:0]);
+            nsummation <= (s_axi_WDATA[5:0] & wmask[5:0]) | (nsummation & !wmask[5:0]);
     end
 end
 
diff --git a/fpga/hls/data_collection_fsm.cpp b/fpga/hls/data_collection_fsm.cpp
index e166b9b1..d2301729 100644
--- a/fpga/hls/data_collection_fsm.cpp
+++ b/fpga/hls/data_collection_fsm.cpp
@@ -15,7 +15,7 @@ void data_collection_fsm(AXI_STREAM &eth_in,
                 ap_uint<32> nframes,
                 ap_uint<8>  nmodules,
                 ap_uint<4>  nstorage_cells,
-                ap_uint<4> nsummation) {
+                ap_uint<6> nsummation) {
 #pragma HLS INTERFACE ap_ctrl_none port=return
 
 #pragma HLS INTERFACE axis register both port=eth_in
diff --git a/fpga/hls/frame_summation.cpp b/fpga/hls/frame_summation.cpp
index 2ce582ca..c15d08aa 100644
--- a/fpga/hls/frame_summation.cpp
+++ b/fpga/hls/frame_summation.cpp
@@ -36,7 +36,7 @@ void frame_summation(STREAM_512 &data_in, STREAM_768 &data_out,
     packet_768_t packet_out;
 
     data_in >> packet_in;
-    ap_uint<4> sum = ACT_REG_NSUMMATION(packet_in.data); // 0..15
+    ap_uint<6> sum = ACT_REG_NSUMMATION(packet_in.data); // 0..63
     data_out << packet_768_t{.data = packet_in.data, .user = 0, .last = 0};
 
     data_in >> packet_in;
diff --git a/fpga/hls/frame_summation_reorder_compl.cpp b/fpga/hls/frame_summation_reorder_compl.cpp
index fdd2a91f..80da8305 100644
--- a/fpga/hls/frame_summation_reorder_compl.cpp
+++ b/fpga/hls/frame_summation_reorder_compl.cpp
@@ -14,7 +14,7 @@ void frame_summation_reorder_compl(STREAM_512 &data_in,
 
     packet_512_t packet_in;
     data_in >> packet_in;
-    ap_uint<4> sum = ACT_REG_NSUMMATION(packet_in.data); // 0..15
+    ap_uint<6> sum = ACT_REG_NSUMMATION(packet_in.data); // 0..63
     data_out << packet_in;
 
     axis_completion completions[MAX_FPGA_SUMMATION * MAX_MODULES_FPGA];
diff --git a/fpga/hls/hls_jfjoch.h b/fpga/hls/hls_jfjoch.h
index 14c82891..05019169 100644
--- a/fpga/hls/hls_jfjoch.h
+++ b/fpga/hls/hls_jfjoch.h
@@ -57,7 +57,7 @@ typedef hls::stream<packet_768_t> STREAM_768;
 #define ACT_REG_NFRAMES(x)                ((x)(95 ,  64)) // 32 bit
 #define ACT_REG_NMODULES(x)               ((x)(132, 128)) // 5 bit (0..31)
 #define ACT_REG_NSTORAGE_CELLS(x)         ((x)(148, 144)) // 5 bit
-#define ACT_REG_NSUMMATION(x)             ((x)(163, 160)) // 4 bit (0..15)
+#define ACT_REG_NSUMMATION(x)             ((x)(165, 160)) // 6 bit (0..63)
 
 struct axis_datamover_ctrl {
     ap_uint<40+64> data;
@@ -278,7 +278,7 @@ void data_collection_fsm(AXI_STREAM &eth_in,
                          ap_uint<32> nframes,
                          ap_uint<8>  nmodules,
                          ap_uint<4>  nstorage_cells,
-                         ap_uint<4> nsummation);
+                         ap_uint<6> nsummation);
 
 void host_writer(STREAM_512 &data_in,
                  hls::stream<ap_uint<512>> &adu_histo_in,