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feat(#13): TigerTag partial write — update only changed pages #164

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Merged
sjordan0228 merged 2 commits into from
Apr 20, 2026
Merged

feat(#13): TigerTag partial write — update only changed pages #164

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5e903f1
feat(#13): TigerTag partial write — update only changed pages
sjordan0228 Apr 19, 2026
be4d171
fix(#13): full-rewrite fallback on partial-run write failure
sjordan0228 Apr 20, 2026
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84 changes: 75 additions & 9 deletions src/NFCManager.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1759,16 +1759,82 @@ bool NFCManager::executeTigerTagWrite(const NFCWriteRequest& request) {
if (!validateWriteUid(request.expected_spool_id, "WRITE_TIGERTAG")) return false;
if (!checkWriteCapacity(4, 10, "WRITE_TIGERTAG")) return false;

bool ok = connection_->writeISO14443Pages(4, 10, request.data.tigertag_data, 40);
if (ok) {
Serial.println("NFCManager: WRITE_TIGERTAG succeeded");
LogBuffer::getInstance().logPrintf("Write TigerTag: OK\n");
forceRescan();
} else {
Serial.println("NFCManager: WRITE_TIGERTAG failed");
LogBuffer::getInstance().logPrintf("Write TigerTag: FAILED\n");
// Pre-read current tag contents so we can write only the pages that actually changed.
// TigerTag has a fixed binary layout across pages 4–13, so byte offsets never shift
// and page-granular partial writes are safe.
uint8_t current[40];
uint16_t bytesRead = connection_->readISO14443Pages(4, 10, current, sizeof(current), true);
if (bytesRead < 40) {
Serial.printf("NFCManager: WRITE_TIGERTAG pre-read returned %u bytes, falling back to full write\n",
bytesRead);
LogBuffer::getInstance().logPrintf("Write TigerTag: pre-read failed, full write\n");
bool ok = connection_->writeISO14443Pages(4, 10, request.data.tigertag_data, 40);
if (ok) {
Serial.println("NFCManager: WRITE_TIGERTAG succeeded");
LogBuffer::getInstance().logPrintf("Write TigerTag: OK\n");
forceRescan();
} else {
Serial.println("NFCManager: WRITE_TIGERTAG failed");
LogBuffer::getInstance().logPrintf("Write TigerTag: FAILED\n");
}
return ok;
}

// Build contiguous runs of changed pages. 10 pages alternating → at most 5 runs.
struct PageRun { uint8_t startPage; uint8_t pageCount; };
PageRun runs[5];
uint8_t runCount = 0;
bool inRun = false;

for (uint8_t i = 0; i < 10; ++i) {
bool changed = memcmp(&request.data.tigertag_data[i * 4], &current[i * 4], 4) != 0;
if (changed) {
if (!inRun) {
runs[runCount].startPage = 4 + i;
runs[runCount].pageCount = 1;
inRun = true;
} else {
runs[runCount].pageCount++;
}
} else if (inRun) {
runCount++;
inRun = false;
}
}
return ok;
if (inRun) runCount++;

if (runCount == 0) {
Serial.println("NFCManager: WRITE_TIGERTAG no changes, skipping write");
LogBuffer::getInstance().logPrintf("Write TigerTag: no changes\n");
return true;
}

uint8_t totalPages = 0;
for (uint8_t r = 0; r < runCount; ++r) {
const PageRun& run = runs[r];
const uint8_t* data = request.data.tigertag_data + (run.startPage - 4) * 4;
if (!connection_->writeISO14443Pages(run.startPage, run.pageCount, data, run.pageCount * 4)) {
Serial.printf("NFCManager: WRITE_TIGERTAG run %u failed (page %u, %u pages), attempting full rewrite\n",
r, run.startPage, run.pageCount);
LogBuffer::getInstance().logPrintf("Write TigerTag: run failed, full rewrite\n");
if (connection_->writeISO14443Pages(4, 10, request.data.tigertag_data, 40)) {
Serial.println("NFCManager: WRITE_TIGERTAG full rewrite succeeded");
LogBuffer::getInstance().logPrintf("Write TigerTag: OK (full rewrite)\n");
forceRescan();
return true;
}
Serial.println("NFCManager: WRITE_TIGERTAG full rewrite failed");
LogBuffer::getInstance().logPrintf("Write TigerTag: FAILED\n");
return false;
}
totalPages += run.pageCount;
}

Serial.printf("NFCManager: WRITE_TIGERTAG wrote %u/10 pages in %u run(s)\n", totalPages, runCount);
LogBuffer::getInstance().logPrintf("Write TigerTag: OK (%u/10 pages, %u run%s)\n",
totalPages, runCount, runCount == 1 ? "" : "s");
forceRescan();
return true;
Comment on lines +1812 to +1837
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@coderabbitai coderabbitai Bot Apr 19, 2026

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⚠️ Potential issue | 🔴 Critical

Add convergence/verification after partial TigerTag writes.

Line 1816 writes each changed run independently, but Line 1820 returns after a failed later run even if earlier runs already changed the tag. Also, Lines 1825-1829 report success without re-reading pages 4-13, so this can return success for an unverified or mixed TigerTag image. Add a full-write fallback on run failure and verify the final 40 bytes before returning true.

🐛 Proposed fix: converge on full write after run failure and verify read-back 
     uint8_t totalPages = 0;
+    bool needsFullWriteFallback = false;
     for (uint8_t r = 0; r < runCount; ++r) {
         const PageRun& run = runs[r];
         const uint8_t* data = request.data.tigertag_data + (run.startPage - 4) * 4;
         if (!connection_->writeISO14443Pages(run.startPage, run.pageCount, data, run.pageCount * 4)) {
             Serial.printf("NFCManager: WRITE_TIGERTAG failed at run %u (page %u, %u pages)\n",
                           r, run.startPage, run.pageCount);
-            LogBuffer::getInstance().logPrintf("Write TigerTag: FAILED\n");
-            return false;
+            LogBuffer::getInstance().logPrintf("Write TigerTag: partial run failed, trying full write\n");
+            needsFullWriteFallback = true;
+            break;
         }
         totalPages += run.pageCount;
     }
+
+    if (needsFullWriteFallback) {
+        if (!connection_->writeISO14443Pages(4, 10, request.data.tigertag_data, 40)) {
+            Serial.println("NFCManager: WRITE_TIGERTAG full-write fallback failed");
+            LogBuffer::getInstance().logPrintf("Write TigerTag: FAILED\n");
+            return false;
+        }
+        totalPages = 10;
+    }
+
+    uint8_t verify[40];
+    uint16_t verifyBytes = connection_->readISO14443Pages(4, 10, verify, sizeof(verify), true);
+    if (verifyBytes < 40 || memcmp(verify, request.data.tigertag_data, sizeof(verify)) != 0) {
+        Serial.printf("NFCManager: WRITE_TIGERTAG verify failed (%u bytes read)\n", verifyBytes);
+        LogBuffer::getInstance().logPrintf("Write TigerTag: VERIFY FAILED\n");
+        return false;
+    }
 
     Serial.printf("NFCManager: WRITE_TIGERTAG wrote %u/10 pages in %u run(s)\n", totalPages, runCount);
📝 Committable suggestion

‼️ IMPORTANT
Carefully review the code before committing. Ensure that it accurately replaces the highlighted code, contains no missing lines, and has no issues with indentation. Thoroughly test & benchmark the code to ensure it meets the requirements.

Suggested change
uint8_t totalPages = 0;
for (uint8_t r = 0; r < runCount; ++r) {
const PageRun& run = runs[r];
const uint8_t* data = request.data.tigertag_data + (run.startPage - 4) * 4;
if (!connection_->writeISO14443Pages(run.startPage, run.pageCount, data, run.pageCount * 4)) {
Serial.printf("NFCManager: WRITE_TIGERTAG failed at run %u (page %u, %u pages)\n",
r, run.startPage, run.pageCount);
LogBuffer::getInstance().logPrintf("Write TigerTag: FAILED\n");
return false;
}
totalPages += run.pageCount;
}
Serial.printf("NFCManager: WRITE_TIGERTAG wrote %u/10 pages in %u run(s)\n", totalPages, runCount);
LogBuffer::getInstance().logPrintf("Write TigerTag: OK (%u/10 pages, %u run%s)\n",
totalPages, runCount, runCount == 1 ? "" : "s");
forceRescan();
return true;
uint8_t totalPages = 0;
bool needsFullWriteFallback = false;
for (uint8_t r = 0; r < runCount; ++r) {
const PageRun& run = runs[r];
const uint8_t* data = request.data.tigertag_data + (run.startPage - 4) * 4;
if (!connection_->writeISO14443Pages(run.startPage, run.pageCount, data, run.pageCount * 4)) {
Serial.printf("NFCManager: WRITE_TIGERTAG failed at run %u (page %u, %u pages)\n",
r, run.startPage, run.pageCount);
LogBuffer::getInstance().logPrintf("Write TigerTag: partial run failed, trying full write\n");
needsFullWriteFallback = true;
break;
}
totalPages += run.pageCount;
}
if (needsFullWriteFallback) {
if (!connection_->writeISO14443Pages(4, 10, request.data.tigertag_data, 40)) {
Serial.println("NFCManager: WRITE_TIGERTAG full-write fallback failed");
LogBuffer::getInstance().logPrintf("Write TigerTag: FAILED\n");
return false;
}
totalPages = 10;
}
uint8_t verify[40];
uint16_t verifyBytes = connection_->readISO14443Pages(4, 10, verify, sizeof(verify), true);
if (verifyBytes < 40 || memcmp(verify, request.data.tigertag_data, sizeof(verify)) != 0) {
Serial.printf("NFCManager: WRITE_TIGERTAG verify failed (%u bytes read)\n", verifyBytes);
LogBuffer::getInstance().logPrintf("Write TigerTag: VERIFY FAILED\n");
return false;
}
Serial.printf("NFCManager: WRITE_TIGERTAG wrote %u/10 pages in %u run(s)\n", totalPages, runCount);
LogBuffer::getInstance().logPrintf("Write TigerTag: OK (%u/10 pages, %u run%s)\n",
totalPages, runCount, runCount == 1 ? "" : "s");
forceRescan();
return true;
🧰 Tools
🪛 Clang (14.0.6)

[warning] 1813-1813: loop variable name 'r' is too short, expected at least 2 characters

(readability-identifier-length)

[warning] 1819-1819: do not call c-style vararg functions

(cppcoreguidelines-pro-type-vararg)

[warning] 1826-1826: do not call c-style vararg functions

(cppcoreguidelines-pro-type-vararg)

🤖 Prompt for AI Agents 
Verify each finding against the current code and only fix it if needed.

In `@src/NFCManager.cpp` around lines 1812 - 1829, The partial-run write loop in
NFCManager (using connection_->writeISO14443Pages and
request.data.tigertag_data) can leave a mixed/partial TigerTag if a later run
fails; modify the logic so that on any run failure you attempt a full-write
fallback of pages 4–13 (all 10 pages) using the original tigertag_data, then
read back the full 40 bytes (pages 4–13) via connection_->readISO14443Pages (or
the existing read method) to verify the contents match
request.data.tigertag_data before reporting success; ensure failure paths still
log via LogBuffer::getInstance().logPrintf and Serial.printf, call forceRescan()
only after verified success, and return false if verification fails.

}

bool NFCManager::executeOpenTag3DWrite(const NFCWriteRequest& request) {
Expand Down