diff --git a/updater/install.cpp b/updater/install.cpp
index 1ac19ce..9d108e0 100644
--- a/updater/install.cpp
+++ b/updater/install.cpp
@@ -262,9 +262,7 @@
 // apply_patch_check(filename, [sha1, ...])
 //   Returns true if the contents of filename or the temporary copy in the cache partition (if
 //   present) have a SHA-1 checksum equal to one of the given sha1 values. sha1 values are
-//   specified as 40 hex digits. This function differs from sha1_check(read_file(filename),
-//   sha1 [, ...]) in that it knows to check the cache partition copy, so apply_patch_check() will
-//   succeed even if the file was corrupted by an interrupted apply_patch() update.
+//   specified as 40 hex digits.
 Value* ApplyPatchCheckFn(const char* name, State* state,
                          const std::vector<std::unique_ptr<Expr>>& argv) {
   if (argv.size() < 1) {
@@ -287,51 +285,6 @@
   return StringValue(result == 0 ? "t" : "");
 }
 
-// sha1_check(data)
-//    to return the sha1 of the data (given in the format returned by
-//    read_file).
-//
-// sha1_check(data, sha1_hex, [sha1_hex, ...])
-//    returns the sha1 of the file if it matches any of the hex
-//    strings passed, or "" if it does not equal any of them.
-//
-Value* Sha1CheckFn(const char* name, State* state, const std::vector<std::unique_ptr<Expr>>& argv) {
-  if (argv.size() < 1) {
-    return ErrorAbort(state, kArgsParsingFailure, "%s() expects at least 1 arg", name);
-  }
-
-  std::vector<std::unique_ptr<Value>> args;
-  if (!ReadValueArgs(state, argv, &args)) {
-    return nullptr;
-  }
-
-  if (args[0]->type == VAL_INVALID) {
-    return StringValue("");
-  }
-  uint8_t digest[SHA_DIGEST_LENGTH];
-  SHA1(reinterpret_cast<const uint8_t*>(args[0]->data.c_str()), args[0]->data.size(), digest);
-
-  if (argv.size() == 1) {
-    return StringValue(print_sha1(digest));
-  }
-
-  for (size_t i = 1; i < argv.size(); ++i) {
-    uint8_t arg_digest[SHA_DIGEST_LENGTH];
-    if (args[i]->type != VAL_STRING) {
-      LOG(ERROR) << name << "(): arg " << i << " is not a string; skipping";
-    } else if (ParseSha1(args[i]->data, arg_digest) != 0) {
-      // Warn about bad args and skip them.
-      LOG(ERROR) << name << "(): error parsing \"" << args[i]->data << "\" as sha-1; skipping";
-    } else if (memcmp(digest, arg_digest, SHA_DIGEST_LENGTH) == 0) {
-      // Found a match.
-      return args[i].release();
-    }
-  }
-
-  // Didn't match any of the hex strings; return false.
-  return StringValue("");
-}
-
 // mount(fs_type, partition_type, location, mount_point)
 // mount(fs_type, partition_type, location, mount_point, mount_options)
 
@@ -1027,7 +980,6 @@
   RegisterFunction("wipe_block_device", WipeBlockDeviceFn);
 
   RegisterFunction("read_file", ReadFileFn);
-  RegisterFunction("sha1_check", Sha1CheckFn);
   RegisterFunction("write_value", WriteValueFn);
 
   RegisterFunction("wipe_cache", WipeCacheFn);