diff --git a/examples/mifare.c b/examples/mifare.c
index 9fcc47e..6f94420 100644
--- a/examples/mifare.c
+++ b/examples/mifare.c
@@ -51,7 +51,7 @@ bool
 nfc_initiator_mifare_cmd (nfc_device_t * pnd, const mifare_cmd mc, const uint8_t ui8Block, mifare_param * pmp)
 {
   byte_t  abtRx[265];
-  size_t  szRx;
+  size_t  szRx = sizeof(abtRx);
   size_t  szParamLen;
   byte_t  abtCmd[265];
   bool    bEasyFraming;
diff --git a/examples/nfc-anticol.c b/examples/nfc-anticol.c
index 40d7e68..b6b2f6a 100644
--- a/examples/nfc-anticol.c
+++ b/examples/nfc-anticol.c
@@ -54,7 +54,7 @@
 
 static byte_t abtRx[MAX_FRAME_LEN];
 static size_t szRxBits;
-static size_t szRx;
+static size_t szRx = sizeof(abtRx);
 static byte_t abtRawUid[12];
 static byte_t abtAtqa[2];
 static byte_t abtSak;
diff --git a/examples/nfc-dep-initiator.c b/examples/nfc-dep-initiator.c
index b2f5006..645ab23 100644
--- a/examples/nfc-dep-initiator.c
+++ b/examples/nfc-dep-initiator.c
@@ -53,7 +53,7 @@ main (int argc, const char *argv[])
   nfc_device_t *pnd;
   nfc_target_t nt;
   byte_t  abtRx[MAX_FRAME_LEN];
-  size_t  szRx;
+  size_t  szRx = sizeof(abtRx);
   byte_t  abtTx[] = "Hello World!";
 
   if (argc > 1) {
diff --git a/examples/nfc-dep-target.c b/examples/nfc-dep-target.c
index 9a74dfa..033120e 100644
--- a/examples/nfc-dep-target.c
+++ b/examples/nfc-dep-target.c
@@ -50,7 +50,7 @@ int
 main (int argc, const char *argv[])
 {
   byte_t  abtRx[MAX_FRAME_LEN];
-  size_t  szRx;
+  size_t  szRx = sizeof(abtRx);
   size_t  szDeviceFound;
   byte_t  abtTx[] = "Hello Mars!";
   nfc_device_t *pnd;
diff --git a/examples/nfc-emulate-forum-tag4.c b/examples/nfc-emulate-forum-tag4.c
index 9b5cb39..b2b5235 100644
--- a/examples/nfc-emulate-forum-tag4.c
+++ b/examples/nfc-emulate-forum-tag4.c
@@ -68,7 +68,7 @@
 #define MAX_FRAME_LEN 264
 
 static byte_t abtRx[MAX_FRAME_LEN];
-static size_t szRx;
+static size_t szRx = sizeof(abtRx);
 static nfc_device_t *pnd;
 static bool quiet_output = false;
 
diff --git a/examples/nfc-emulate-tag.c b/examples/nfc-emulate-tag.c
index 9c4935d..bf19e81 100644
--- a/examples/nfc-emulate-tag.c
+++ b/examples/nfc-emulate-tag.c
@@ -56,7 +56,7 @@
 #define SAK_ISO14443_4_COMPLIANT 0x20
 
 static byte_t abtRx[MAX_FRAME_LEN];
-static size_t szRx;
+static size_t szRx = sizeof(abtRx);
 static nfc_device_t *pnd;
 static bool quiet_output = false;
 static bool init_mfc_auth = false;
diff --git a/examples/pn53x-diagnose.c b/examples/pn53x-diagnose.c
index 735f21a..f930d53 100644
--- a/examples/pn53x-diagnose.c
+++ b/examples/pn53x-diagnose.c
@@ -55,7 +55,7 @@ main (int argc, const char *argv[])
   bool    result;
 
   byte_t  abtRx[PN53x_EXTENDED_FRAME__DATA_MAX_LEN];
-  size_t  szRx;
+  size_t  szRx = sizeof(abtRx);
   const byte_t pncmd_diagnose_communication_line_test[] = { 0xD4, 0x00, 0x00, 0x06, 'l', 'i', 'b', 'n', 'f', 'c' };
   const byte_t pncmd_diagnose_rom_test[] = { 0xD4, 0x00, 0x01 };
   const byte_t pncmd_diagnose_ram_test[] = { 0xD4, 0x00, 0x02 };
diff --git a/examples/pn53x-sam.c b/examples/pn53x-sam.c
index e981dd3..38bb320 100644
--- a/examples/pn53x-sam.c
+++ b/examples/pn53x-sam.c
@@ -74,7 +74,7 @@ sam_connection (nfc_device_t * pnd, int mode)
   size_t  szCmd = 0;
 
   byte_t  abtRx[MAX_FRAME_LEN];
-  size_t  szRx;
+  size_t  szRx = sizeof(abtRx);
 
   pncmd_sam_config[2] = mode;
 
@@ -210,7 +210,7 @@ main (int argc, const char *argv[])
   case DUAL_CARD_MODE:
     {
       byte_t  abtRx[MAX_FRAME_LEN];
-      size_t  szRx;
+      size_t  szRx = sizeof(abtRx);
 
       nfc_target_t nt = {
         .nm = {
diff --git a/examples/pn53x-tamashell.c b/examples/pn53x-tamashell.c
index 4a0410d..d6df7cf 100644
--- a/examples/pn53x-tamashell.c
+++ b/examples/pn53x-tamashell.c
@@ -63,7 +63,7 @@ int main(int argc, const char* argv[])
   nfc_device_t* pnd;
   byte_t abtRx[MAX_FRAME_LEN];
   byte_t abtTx[MAX_FRAME_LEN] = { 0xD4 };
-  size_t szRx;
+  size_t szRx = sizeof(abtRx);
   size_t szTx;
   extern FILE* stdin;
   FILE* input = NULL;
diff --git a/libnfc/drivers/arygon.c b/libnfc/drivers/arygon.c
index eb868df..b73e9a8 100644
--- a/libnfc/drivers/arygon.c
+++ b/libnfc/drivers/arygon.c
@@ -371,7 +371,7 @@ void
 arygon_ack (const nfc_device_spec_t nds)
 {
   byte_t abtRx[BUFFER_LENGTH];
-  size_t szRx;
+  size_t szRx = sizeof(abtRx);
 #ifdef DEBUG
   PRINT_HEX ("TX", arygon_ack_frame, sizeof (arygon_ack_frame));
 #endif
@@ -392,7 +392,7 @@ bool
 arygon_check_communication (const nfc_device_spec_t nds)
 {
   byte_t  abtRx[RX_BUFFER_LENGTH];
-  size_t  szRx;
+  size_t  szRx = sizeof(abtRx);
   const byte_t attempted_result[] = { 0x00, 0x00, 0xff, 0x00, 0xff, 0x00, // ACK
     0x00, 0x00, 0xff, 0x09, 0xf7, 0xd5, 0x01, 0x00, 'l', 'i', 'b', 'n', 'f', 'c', 0xbc, 0x00 }; // Reply
   int     res;