diff --git a/src/GSLArchive.cc b/src/GSLArchive.cc
index 0104dffb..06df2e04 100644
--- a/src/GSLArchive.cc
+++ b/src/GSLArchive.cc
@@ -10,20 +10,20 @@ using namespace std;
 
 
 
-// TODO: Support big-endian GSLs also (e.g. from PSO GC)
-
+template <typename LongT>
 struct GSLHeaderEntry {
   ptext<char, 0x20> filename;
-  le_uint32_t offset; // In pages, so actual offset is this * 0x800
-  le_uint32_t size;
+  LongT offset; // In pages, so actual offset is this * 0x800
+  LongT size;
   uint64_t unused;
-};
+} __attribute__((packed));
 
-GSLArchive::GSLArchive(shared_ptr<const string> data) : data(data) {
+template <typename LongT>
+void GSLArchive::load_t() {
   StringReader r(*this->data);
   uint64_t min_data_offset = 0xFFFFFFFFFFFFFFFF;
   while (r.where() < min_data_offset) {
-    const auto& entry = r.get<GSLHeaderEntry>();
+    const auto& entry = r.get<GSLHeaderEntry<LongT>>();
     if (entry.filename.len() == 0) {
       break;
     }
@@ -35,6 +35,15 @@ GSLArchive::GSLArchive(shared_ptr<const string> data) : data(data) {
   }
 }
 
+GSLArchive::GSLArchive(shared_ptr<const string> data, bool big_endian)
+  : data(data) {
+  if (big_endian) {
+    this->load_t<be_uint32_t>();
+  } else {
+    this->load_t<le_uint32_t>();
+  }
+}
+
 const unordered_map<string, GSLArchive::Entry> GSLArchive::all_entries() const {
   return this->entries;
 }
diff --git a/src/GSLArchive.hh b/src/GSLArchive.hh
index 4f0635dc..96c863b4 100644
--- a/src/GSLArchive.hh
+++ b/src/GSLArchive.hh
@@ -12,7 +12,7 @@
 
 class GSLArchive {
 public:
-  GSLArchive(std::shared_ptr<const std::string> data);
+  GSLArchive(std::shared_ptr<const std::string> data, bool big_endian);
   ~GSLArchive() = default;
 
   struct Entry {
@@ -26,6 +26,9 @@ public:
   StringReader get_reader(const std::string& name) const;
 
 private:
+  template <typename LongT>
+  void load_t();
+
   std::shared_ptr<const std::string> data;
 
   std::unordered_map<std::string, Entry> entries;
diff --git a/src/Main.cc b/src/Main.cc
index db088d21..d9582d74 100644
--- a/src/Main.cc
+++ b/src/Main.cc
@@ -364,9 +364,8 @@ The options are:\n\
       Extract all files from a GSL archive into the current directory.\n\
       input-filename may be specified. If output-filename is specified, then it\n\
       is treated as a prefix which is prepended to the filename of each file\n\
-      contained in the GSL archive. Importantly, if you want to put the files\n\
-      into a directory, you'll have to create the directory first, and include\n\
-      a trailing / on output-filename.\n\
+      contained in the GSL archive. If --big-endian is given, the GSL header is\n\
+      read in GameCube format; otherwise it is read in PC/BB format.\n\
 \n\
 A few options apply to multiple modes described above:\n\
   --parse-data\n\
@@ -825,7 +824,7 @@ int main(int argc, char** argv) {
       string data = read_input_data();
 
       shared_ptr<string> data_shared(new string(move(data)));
-      GSLArchive gsl(data_shared);
+      GSLArchive gsl(data_shared, big_endian);
       for (const auto& entry_it : gsl.all_entries()) {
         auto e = gsl.get(entry_it.first);
         save_file(output_filename + entry_it.first, e.first, e.second);
@@ -930,7 +929,7 @@ int main(int argc, char** argv) {
         state->bb_patch_file_index.reset(new PatchFileIndex("system/patch-bb"));
         try {
           auto gsl_file = state->bb_patch_file_index->get("./data/data.gsl");
-          state->bb_data_gsl.reset(new GSLArchive(gsl_file->load_data()));
+          state->bb_data_gsl.reset(new GSLArchive(gsl_file->load_data(), false));
           config_log.info("data.gsl found in BB patch files");
         } catch (const out_of_range&) {
           config_log.info("data.gsl is not present in BB patch files");