diff --git a/sonixflasher.c b/sonixflasher.c
index 4819d51..c5a7cda 100644
--- a/sonixflasher.c
+++ b/sonixflasher.c
@@ -37,6 +37,7 @@
 #define USER_ROM_PAGES_SN32F290 256
 
 #define QMK_OFFSET_DEFAULT 0x200
+#define MIN_FIRMWARE 0x100
 
 #define CMD_BASE 0x55AA
 #define CMD_GET_FW_VERSION 0x1
@@ -51,7 +52,7 @@
 #define CMD_VERIFY(x) ((CMD_BASE << 8) | (x))
 
 #define CMD_ACK 0xFAFAFAFA
-#define VALID_FW 0xAAAA5555
+#define LAST_CHUNK_OFFSET (REPORT_SIZE - sizeof(uint32_t))
 
 #define SN240 1
 #define SN260 2
@@ -657,12 +658,21 @@ bool flash(hid_device *dev, long offset, const char *file_name, long fw_size, bo
 
     size_t   bytes_read = 0;
     uint16_t checksum   = 0;
+    uint32_t last_chunk = 0;
     clear_buffer(buf, REPORT_SIZE);
     while ((bytes_read = fread(buf, 1, REPORT_SIZE, firmware)) > 0) {
         if (bytes_read < REPORT_SIZE) {
             fprintf(stderr, "WARNING: Read %zu bytes, expected %d bytes.\n", bytes_read, REPORT_SIZE);
         }
         checksum += checksum16(buf, bytes_read);
+
+        // Capture the last 4 bytes of this buffer for last_chunk
+        if (bytes_read >= sizeof(uint32_t)) {
+            memcpy(&last_chunk, buf + (bytes_read - sizeof(uint32_t)), sizeof(uint32_t));
+        } else {
+            memcpy(&last_chunk, buf, bytes_read);
+        }
+
         if (!hid_set_feature(dev, buf, bytes_read)) return false;
 
         clear_buffer(buf, REPORT_SIZE);
@@ -675,19 +685,23 @@ bool flash(hid_device *dev, long offset, const char *file_name, long fw_size, bo
     printf("\n");
     printf("Verifying flash completion...\n");
     if (!hid_get_feature(dev, buf, REPORT_SIZE, CMD_ENABLE_PROGRAM)) return false;
-    if (read_response_32(buf, (sizeof(buf) - sizeof(VALID_FW)), VALID_FW, &resp)) {
+    if (read_response_32(buf, LAST_CHUNK_OFFSET, last_chunk, &resp)) {
         printf("Flash completion verified. \n");
         uint16_t resp_16 = (uint16_t)resp;
         if (read_response_16(buf, 8, checksum, &resp_16)) {
             printf("Flash Verification Checksum: OK!\n");
             return true;
         } else {
+            if (offset != 0) {
+                printf("Warning: offset 0x%04lx requested. Flash Verification Checksum disabled.\n", offset);
+                return true;
+            }
             fprintf(stderr, "ERROR:Flash Verification Checksum: FAILED! response is 0x%04x, expected 0x%04x.\n", resp_16, checksum);
             return false;
         }
         return false;
     } else {
-        fprintf(stderr, "ERROR: Failed to verify flash completion: response is 0x%08x, expected 0x%08x.\n", resp, VALID_FW);
+        fprintf(stderr, "ERROR: Failed to verify flash completion: response is 0x%08x, expected 0x%08x.\n", resp, last_chunk);
         return false;
     }
     return false;
@@ -717,7 +731,7 @@ bool sanity_check_firmware(long fw_size, long offset) {
         fprintf(stderr, "ERROR: Firmware is too large too flash: 0x%08lx max allowed is 0x%08lx.\n", fw_size, MAX_FIRMWARE - offset);
         return false;
     }
-    if (fw_size < 0x100) {
+    if (fw_size < MIN_FIRMWARE) {
         fprintf(stderr, "ERROR: Firmware is too small.");
         return false;
     }
@@ -757,6 +771,22 @@ long get_file_size(FILE *fp) {
     return file_size;
 }
 
+bool truncate_and_reopen(const char *file_name, FILE **fp, long new_size) {
+    fclose(*fp); // Close the file before truncating
+    if (truncate(file_name, new_size) != 0) {
+        fprintf(stderr, "ERROR: Could not truncate file to size %ld.\n", new_size);
+        return false;
+    }
+
+    *fp = fopen(file_name, "rb"); // Reopen the file in read mode
+    if (*fp == NULL) {
+        fprintf(stderr, "ERROR: Could not reopen file after truncation.\n");
+        return false;
+    }
+
+    return true;
+}
+
 long prepare_file_to_flash(const char *file_name, bool flash_jumploader) {
     FILE *fp = fopen(file_name, "rb");
     if (fp == NULL) {
@@ -783,22 +813,14 @@ long prepare_file_to_flash(const char *file_name, bool flash_jumploader) {
         printf("Warning: jumploader binary doesn't have a size of: 0x%04x bytes.\n", QMK_OFFSET_DEFAULT);
         printf("Truncating jumploader binary to: 0x%04x.\n", QMK_OFFSET_DEFAULT);
 
-        fclose(fp);
-        if (truncate(file_name, QMK_OFFSET_DEFAULT) != 0) {
-            fprintf(stderr, "ERROR: Could not truncate file.\n");
-            return -1;
-        }
-
-        // Reopen the file
-        fp = fopen(file_name, "rb");
-        if (fp == NULL) {
-            fprintf(stderr, "ERROR: Could not open file after truncation.\n");
+        if (!truncate_and_reopen(file_name, &fp, QMK_OFFSET_DEFAULT)) {
             return -1;
         }
 
         // Recalculate file size
         file_size = get_file_size(fp);
         if (file_size == -1L) {
+            fprintf(stderr, "ERROR: Truncated file size calculation failed.\n");
             fclose(fp);
             return -1;
         }
@@ -813,7 +835,18 @@ long prepare_file_to_flash(const char *file_name, bool flash_jumploader) {
             padded_file_size++;
         }
         printf("File size after padding: %ld bytes\n", padded_file_size);
-        file_size = padded_file_size;
+
+        if (!truncate_and_reopen(file_name, &fp, padded_file_size)) {
+            return -1;
+        }
+
+        // Recalculate file size
+        file_size = get_file_size(fp);
+        if (file_size == -1L) {
+            fprintf(stderr, "ERROR: Truncated file size calculation failed.\n");
+            fclose(fp);
+            return -1;
+        }
     }
 
     fclose(fp);