diff --git a/scum_programmer/nrf-fw/hdlc.c b/scum_programmer/nrf-fw/hdlc.c
index f8bfa10..8746189 100644
--- a/scum_programmer/nrf-fw/hdlc.c
+++ b/scum_programmer/nrf-fw/hdlc.c
@@ -4,17 +4,17 @@
 
 //=========================== definitions ======================================
 
-#define HDLC_BUFFER_SIZE    (UINT8_MAX)  ///< Maximum size of the RX buffer
-#define HDLC_FLAG           (0x7E)       ///< Start/End flag
-#define HDLC_FLAG_ESCAPED   (0x5E)       ///< Start/End flag escaped
-#define HDLC_ESCAPE         (0x7D)       ///< Data escape byte
-#define HDLC_ESCAPE_ESCAPED (0x5D)       ///< Escape flag escaped
-#define HDLC_FCS_INIT       (0xFFFF)     ///< Initialization value of the FCS
-#define HDLC_FCS_OK         (0xF0B8)     ///< Expected value of the FCS
+#define HDLC_BUFFER_SIZE    (2048U)   ///< Maximum size of the RX buffer
+#define HDLC_FLAG           (0x7E)    ///< Start/End flag
+#define HDLC_FLAG_ESCAPED   (0x5E)    ///< Start/End flag escaped
+#define HDLC_ESCAPE         (0x7D)    ///< Data escape byte
+#define HDLC_ESCAPE_ESCAPED (0x5D)    ///< Escape flag escaped
+#define HDLC_FCS_INIT       (0xFFFF)  ///< Initialization value of the FCS
+#define HDLC_FCS_OK         (0xF0B8)  ///< Expected value of the FCS
 
 typedef struct {
     uint8_t buffer[HDLC_BUFFER_SIZE];  ///< Input buffer
-    uint8_t buffer_pos;                ///< Current position in the input buffer
+    uint16_t buffer_pos;               ///< Current position in the input buffer
     hdlc_state_t state;                ///< Current state of the HDLC RX engine
     uint16_t fcs;                      ///< Current value of the FCS
 } hdlc_vars_t;
@@ -103,7 +103,7 @@ size_t hdlc_decode(uint8_t *output) {
         return output_pos;
     }
 
-    uint8_t input_pos = 0;
+    uint16_t input_pos = 0;
     bool escape_byte = false;
     while (input_pos < _hdlc_vars.buffer_pos) {
         uint8_t current_byte = _hdlc_vars.buffer[input_pos];
diff --git a/scum_programmer/nrf-fw/scum-programmer.c b/scum_programmer/nrf-fw/scum-programmer.c
index af521df..5915710 100644
--- a/scum_programmer/nrf-fw/scum-programmer.c
+++ b/scum_programmer/nrf-fw/scum-programmer.c
@@ -15,8 +15,8 @@ SCuM programmer.
 //=========================== defines =========================================
 
 #define UART_BUF_SIZE    (32U)
-#define COMMAND_BUF_SIZE (256U)
-#define CHUNK_SIZE       (128U)
+#define COMMAND_BUF_SIZE (2048U)
+#define CHUNK_SIZE       (1024U)
 #define SCUM_MEM_SIZE    (1 << 16)  // 64KiB
 
 #define CALIBRATION_PORT    0UL
diff --git a/scum_programmer/programmer/scum.py b/scum_programmer/programmer/scum.py
index c3c952a..58a0f76 100644
--- a/scum_programmer/programmer/scum.py
+++ b/scum_programmer/programmer/scum.py
@@ -12,7 +12,7 @@
 
 # Constants
 USB_CHUNK_SIZE = 64
-CHUNK_SIZE = 128
+CHUNK_SIZE = 1024
 
 
 class Command(IntEnum):