diff --git a/armsrc/Standalone/hf_colin.c b/armsrc/Standalone/hf_colin.c
index 6e2d6723c..1dab49959 100644
--- a/armsrc/Standalone/hf_colin.c
+++ b/armsrc/Standalone/hf_colin.c
@@ -98,9 +98,9 @@ static int colin_currfline;
 static int colin_curlline;
 static int cjat91_saMifareChkKeys(uint8_t blockNo, uint8_t keyType, bool clearTrace, uint8_t keyCount, const uint8_t *datain, uint64_t *key);
 static int e_MifareECardLoad(uint32_t numofsectors, uint8_t keytype);
-static void saMifareMakeTag(void);
+static void __attribute__((noinline)) saMifareMakeTag(void);
 static int saMifareCSetBlock(uint32_t arg0, uint32_t arg1, uint32_t arg2, const uint8_t *datain);
-static void WriteTagToFlash(uint32_t uid, size_t size);
+static void __attribute__((noinline)) WriteTagToFlash(uint32_t uid, size_t size);
 
 // TODO : Implement fast read of KEYS like in RFIdea
 // also http://ext.delaat.net/rp/2015-2016/p04/report.pdf
@@ -261,7 +261,7 @@ static char *ReadSchemasFromSPIFFS(char *filename) {
     return (char *)mem;
 }
 
-static void add_schemas_from_json_in_spiffs(char *filename) {
+static void __attribute__((noinline)) add_schemas_from_json_in_spiffs(char *filename) {
 
     const char *jsonfile = ReadSchemasFromSPIFFS((char *)filename);
 
@@ -281,7 +281,7 @@ static void add_schemas_from_json_in_spiffs(char *filename) {
     }
 }
 
-static void ReadLastTagFromFlash(void) {
+static void __attribute__((noinline)) ReadLastTagFromFlash(void) {
     SpinOff(0);
     LED_A_ON();
     LED_B_ON();
@@ -307,7 +307,7 @@ static void ReadLastTagFromFlash(void) {
     return;
 }
 
-static void WriteTagToFlash(uint32_t uid, size_t size) {
+static void __attribute__((noinline)) WriteTagToFlash(uint32_t uid, size_t size) {
     SpinOff(0);
     LED_A_ON();
     LED_B_ON();
@@ -315,7 +315,17 @@ static void WriteTagToFlash(uint32_t uid, size_t size) {
     LED_D_ON();
 
     uint32_t len = size;
-    uint8_t data[(size * (16 * 64)) / 1024];
+
+    // this used to be a VLA - `uint8_t data[(size * (16 * 64)) / 1024]` - which put
+    // another `size` bytes (1024 at the only call site) on top of RunMod's already
+    // 2.5 kB frame, and did not show up in -fstack-usage as anything but "dynamic".
+    uint8_t *data = BigBuf_calloc((size * (16 * 64)) / 1024);
+    if (data == NULL) {
+        DbprintfEx(FLAG_NEWLINE, "[!!] out of memory, tag NOT written to flash");
+        cjSetCursLeft();
+        SpinOff(0);
+        return;
+    }
 
     emlGetMem_xt(data, 0, (size * 64) / 1024, MIFARE_BLOCK_SIZE);
 
@@ -864,7 +874,7 @@ static int cjat91_saMifareChkKeys(uint8_t blockNo, uint8_t keyType, bool clearTr
     return retval;
 }
 
-static void saMifareMakeTag(void) {
+static void __attribute__((noinline)) saMifareMakeTag(void) {
     uint8_t cfail = 0;
     cjSetCursLeft();
     cjTabulize();