diff --git a/src/util/iso_reader.cpp b/src/util/iso_reader.cpp
index 7c0eda909..ab77a0d55 100644
--- a/src/util/iso_reader.cpp
+++ b/src/util/iso_reader.cpp
@@ -370,9 +370,8 @@ bool IsoReader::ReadFile(const ISODirectoryEntry& de, std::vector<u8>* data, Err
     return true;
   }
 
-  static_assert(sizeof(size_t) == sizeof(u64));
   const u32 num_sectors = (de.length_le + (SECTOR_SIZE - 1)) / SECTOR_SIZE;
-  data->resize(num_sectors * static_cast<u64>(SECTOR_SIZE));
+  data->resize(num_sectors * static_cast<size_t>(SECTOR_SIZE));
   for (u32 i = 0, lsn = de.location_le; i < num_sectors; i++, lsn++)
   {
     if (!ReadSector(data->data() + (i * SECTOR_SIZE), lsn, error))