diff --git a/scripts/generate-font-manifest.py b/scripts/generate-font-manifest.py
index 695bb99b..e962c162 100755
--- a/scripts/generate-font-manifest.py
+++ b/scripts/generate-font-manifest.py
@@ -21,6 +21,7 @@ import json
 import os
 import struct
 import sys
+import zlib
 from pathlib import Path
 
 # Import canonical version constants from the shared file in lib/EpdFont/scripts/
@@ -115,6 +116,15 @@ def parse_filename(filename: str) -> tuple[str, str] | None:
     return family, size_str
 
 
+def compute_crc32(filepath: Path) -> int:
+    """Compute CRC32 of a file, matching esp_rom_crc32_le(0xFFFFFFFF, ...) ^ 0xFFFFFFFF."""
+    crc = 0
+    with open(filepath, "rb") as f:
+        for chunk in iter(lambda: f.read(65536), b""):
+            crc = zlib.crc32(chunk, crc)
+    return crc & 0xFFFFFFFF
+
+
 def scan_cpfont_files(input_dir: Path) -> dict[str, list[Path]]:
     """Scan input directory for .cpfont files, grouped by family name.
 
@@ -164,6 +174,7 @@ def build_manifest(
                 {
                     "name": filepath.name,
                     "size": filepath.stat().st_size,
+                    "crc32": compute_crc32(filepath),
                 }
             )
 
diff --git a/src/activities/settings/FontDownloadActivity.cpp b/src/activities/settings/FontDownloadActivity.cpp
index e7419c0e..ce18ce67 100644
--- a/src/activities/settings/FontDownloadActivity.cpp
+++ b/src/activities/settings/FontDownloadActivity.cpp
@@ -6,6 +6,7 @@
 #include <I18n.h>
 #include <Logging.h>
 #include <WiFi.h>
+#include <esp_rom_crc.h>
 
 #include "MappedInputManager.h"
 #include "SdCardFontGlobals.h"
@@ -123,6 +124,14 @@ bool FontDownloadActivity::fetchAndParseManifest() {
       ManifestFile file;
       file.name = fileObj["name"] | "";
       file.size = fileObj["size"] | 0;
+
+      if (!fileObj["crc32"].is<uint32_t>()) {
+        LOG_ERR("FONT", "Malformed manifest file entry: missing or invalid crc32 for %s", file.name.c_str());
+        errorMessage_ = "Invalid font manifest";
+        return false;
+      }
+      file.crc32 = fileObj["crc32"].as<uint32_t>();
+
       family.totalSize += file.size;
       family.files.push_back(std::move(file));
     }
@@ -181,6 +190,24 @@ size_t FontDownloadActivity::totalUninstalledSize() const {
   return total;
 }
 
+// Standard CRC32 matching zlib/Python zlib.crc32().
+bool FontDownloadActivity::computeFileCrc32(const char* path, uint32_t& outCrc) {
+  FsFile f;
+  if (!Storage.openFileForRead("FONT", path, f)) {
+    return false;
+  }
+  constexpr size_t BUF_SIZE = 128;
+  uint8_t buf[BUF_SIZE];
+  uint32_t crc = 0;
+  while (f.available()) {
+    const int n = f.read(buf, BUF_SIZE);
+    if (n <= 0) break;
+    crc = esp_rom_crc32_le(crc, buf, static_cast<uint32_t>(n));
+  }
+  outCrc = crc;
+  return true;
+}
+
 void FontDownloadActivity::downloadFamily(ManifestFamily& family) {
   {
     RenderLock lock(*this);
@@ -233,6 +260,29 @@ void FontDownloadActivity::downloadFamily(ManifestFamily& family) {
       return;
     }
 
+    uint32_t actualCrc = 0;
+    if (!computeFileCrc32(destPath, actualCrc)) {
+      LOG_ERR("FONT", "Failed to open file for CRC check: %s", destPath);
+      fontInstaller_.deleteFamily(family.name.c_str());
+      family.installed = false;
+      family.hasUpdate = false;
+      RenderLock lock(*this);
+      state_ = ERROR;
+      errorMessage_ = "Failed to compute checksum: " + file.name;
+      return;
+    }
+    if (actualCrc != file.crc32) {
+      LOG_ERR("FONT", "CRC32 mismatch for %s: got %08x expected %08x", file.name.c_str(), actualCrc, file.crc32);
+      fontInstaller_.deleteFamily(family.name.c_str());
+      family.installed = false;
+      family.hasUpdate = false;
+      RenderLock lock(*this);
+      state_ = ERROR;
+      errorMessage_ = "Checksum mismatch: " + file.name;
+      return;
+    }
+    LOG_DBG("FONT", "Downloaded %s (size=%zu crc32=%08x)", file.name.c_str(), file.size, actualCrc);
+
     if (!fontInstaller_.validateCpfontFile(destPath)) {
       LOG_ERR("FONT", "Invalid .cpfont: %s", destPath);
       fontInstaller_.deleteFamily(family.name.c_str());
diff --git a/src/activities/settings/FontDownloadActivity.h b/src/activities/settings/FontDownloadActivity.h
index 1b4373c4..16d52fa9 100644
--- a/src/activities/settings/FontDownloadActivity.h
+++ b/src/activities/settings/FontDownloadActivity.h
@@ -50,6 +50,7 @@ class FontDownloadActivity : public Activity {
   struct ManifestFile {
     std::string name;
     size_t size = 0;
+    uint32_t crc32 = 0;
   };
 
   struct ManifestFamily {
@@ -83,6 +84,7 @@ class FontDownloadActivity : public Activity {
   bool fetchAndParseManifest();
   void downloadFamily(ManifestFamily& family);
   void downloadAll();
+  static bool computeFileCrc32(const char* path, uint32_t& outCrc);
   bool isDownloadAllSelected() const { return selectedIndex_ == 0 && !families_.empty(); }
   int familyIndexFromList(int listIndex) const { return listIndex - 1; }
   int listItemCount() const { return families_.empty() ? 0 : static_cast<int>(families_.size()) + 1; }