diff --git a/native/jni/magiskboot/bootimg.cpp b/native/jni/magiskboot/bootimg.cpp
index 6d3022201..bd925ef0d 100644
--- a/native/jni/magiskboot/bootimg.cpp
+++ b/native/jni/magiskboot/bootimg.cpp
@@ -554,7 +554,7 @@ void repack(const char *src_img, const char *out_img, bool skip_comp) {
         if (boot.flags[ZIMAGE_KERNEL] &&
             boot.k_fmt == GZIP && hdr->kernel_size() > boot.hdr->kernel_size()) {
             // Revert and try zipfoli
-            ftruncate(fd, lseek(fd, -hdr->kernel_size(), SEEK_CUR));
+            ftruncate64(fd, lseek64(fd, -(off64_t)hdr->kernel_size(), SEEK_CUR));
             hdr->kernel_size() = compress(ZOPFLI, fd, raw_buf, raw_size);
         }
 
@@ -563,7 +563,7 @@ void repack(const char *src_img, const char *out_img, bool skip_comp) {
     if (boot.flags[ZIMAGE_KERNEL]) {
         if (hdr->kernel_size() > boot.hdr->kernel_size()) {
             LOGW("Recompressed kernel is too large, using original kernel\n");
-            ftruncate(fd, lseek(fd, -hdr->kernel_size(), SEEK_CUR));
+            ftruncate64(fd, lseek64(fd, -(off64_t)hdr->kernel_size(), SEEK_CUR));
             hdr->kernel_size() = xwrite(fd, boot.z_info.tail - boot.hdr->kernel_size(), boot.hdr->kernel_size());
         } else {
             write_zero(fd, boot.hdr->kernel_size() - hdr->kernel_size() - 4);
diff --git a/native/jni/utils/missing.cpp b/native/jni/utils/missing.cpp
index 87ce2a333..41f3d1e8f 100644
--- a/native/jni/utils/missing.cpp
+++ b/native/jni/utils/missing.cpp
@@ -129,6 +129,19 @@ int faccessat(int dirfd, const char *pathname, int mode, int flags) {
     return syscall(__NR_faccessat, dirfd, pathname, mode, flags);
 }
 
+#define SPLIT_64(v) (unsigned)((v) & 0xFFFFFFFF), (unsigned)((v) >> 32)
+
+#if defined(__arm__)
+// Why the additional 0 is required: https://man7.org/linux/man-pages/man2/syscall.2.html
+int ftruncate64(int fd, off64_t length) {
+    return syscall(__NR_ftruncate64, fd, 0, SPLIT_64(length));
+}
+#elif defined(__i386__)
+int ftruncate64(int fd, off64_t length) {
+    return syscall(__NR_ftruncate64, fd, SPLIT_64(length));
+}
+#endif
+
 #if !defined(__LP64__)
 void android_set_abort_message(const char *msg) {}
 #endif