diff --git a/src/keel/pack.cpp b/src/keel/pack.cpp
index 252a0dad1..c35c44509 100644
--- a/src/keel/pack.cpp
+++ b/src/keel/pack.cpp
@@ -165,71 +165,6 @@ static ox::Error copyFS(ox::FileSystem *src, ox::FileSystem *dest) noexcept {
 	return {};
 }
 
-// transformations need to be done after the copy to the new FS is complete
-static ox::Error preloadObj(
-		ox::TypeStore *ts, ox::FileSystem *romFs,
-		GbaPreloader *pl, ox::CRStringView path) noexcept {
-	// load file
-	oxRequireM(buff, romFs->read(path));
-	oxRequireM(obj, keel::readAsset(ts, buff));
-	if (obj.type()->preloadable) {
-		oxOutf("preloading {}\n", path);
-		// preload
-		oxRequire(a, pl->startAlloc(ox::sizeOf<GbaPlatSpec>(&obj)));
-		const auto err = ox::preload<GbaPlatSpec, decltype(obj)>(pl, &obj);
-		oxReturnError(pl->endAlloc());
-		oxReturnError(err);
-		const keel::PreloadPtr p{.preloadAddr = static_cast<uint32_t>(a)};
-		oxReturnError(ox::writeMC(&p).moveTo(&buff));
-	} else {
-		// strip the Claw header (it is not needed after preloading) and write back out to dest fs
-		oxReturnError(ox::writeMC(&obj).moveTo(&buff));
-	}
-	oxReturnError(romFs->write(path, buff.data(), buff.size()));
-	return {};
-}
-
-// claw file transformations are broken out because path to inode
-// transformations need to be done after the copy to the new FS is complete
-static ox::Error preloadDir(ox::TypeStore *ts, ox::FileSystem *romFs, GbaPreloader *pl, ox::CRStringView path) noexcept {
-	// copy
-	oxTracef("pack::preload", "path: {}", path);
-	oxRequire(fileList, romFs->ls(path));
-	for (const auto &name : fileList) {
-		const auto filePath = ox::sfmt("{}{}", path, name);
-		oxRequire(stat, romFs->stat(filePath));
-		if (stat.fileType == ox::FileType::Directory) {
-			const auto dir = ox::sfmt("{}{}/", path, name);
-			oxReturnError(preloadDir(ts, romFs, pl, dir));
-		} else {
-			oxReturnError(preloadObj(ts, romFs, pl, filePath));
-		}
-	}
-	return {};
-}
-
-static ox::Error padbin(ox::BufferWriter *w, unsigned factor) noexcept {
-	return w->write(nullptr, factor - w->buff().size() % factor);
-}
-
-ox::Error appendBinary(ox::Buffer *binBuff, ox::Buffer *fsBuff, GbaPreloader *pl) noexcept {
-	constexpr ox::StringView mediaHdr   = "KEEL_MEDIA_HEADER_______________";
-	constexpr ox::StringView preloadHdr = "KEEL_PRELOAD_HEADER_____________";
-	constexpr auto hdrSize = 32u;
-	static_assert(mediaHdr.bytes() == hdrSize);
-	static_assert(preloadHdr.bytes() == hdrSize);
-	ox::BufferWriter w(binBuff);
-	oxReturnError(padbin(&w, hdrSize));
-	oxReturnError(w.write(mediaHdr.data(), mediaHdr.bytes()));
-	oxReturnError(w.write(fsBuff->data(), fsBuff->size()));
-	oxReturnError(padbin(&w, hdrSize));
-	oxReturnError(w.write(preloadHdr.data(), preloadHdr.bytes()));
-	const auto &plBuff = pl->buff();
-	oxReturnError(pl->offsetPtrs(binBuff->size()));
-	oxReturnError(w.write(plBuff.data(), plBuff.size()));
-	return {};
-}
-
 ox::Error pack(keel::Context *ctx, ox::TypeStore *ts, ox::FileSystem *dest) noexcept {
 	oxReturnError(copyFS(ctx->rom.get(), dest));
 	oxOut("Doing transforms\n");
@@ -237,11 +172,6 @@ ox::Error pack(keel::Context *ctx, ox::TypeStore *ts, ox::FileSystem *dest) noex
 	return {};
 }
 
-ox::Error preload(ox::TypeStore *ts, ox::FileSystem *src, GbaPreloader *pl) noexcept {
-	oxOut("Preloading\n");
-	return preloadDir(ts, src, pl, "/");
-}
-
 }
 
 #endif
diff --git a/src/keel/pack.hpp b/src/keel/pack.hpp
index e3d21dc0f..5380dc354 100644
--- a/src/keel/pack.hpp
+++ b/src/keel/pack.hpp
@@ -7,6 +7,9 @@
 #include <ox/fs/fs.hpp>
 #include <ox/preloader/preloader.hpp>
 
+#include "asset.hpp"
+#include "media.hpp"
+
 namespace keel {
 
 class Context;
@@ -76,10 +79,88 @@ struct GbaPlatSpec {
 
 using GbaPreloader = ox::Preloader<GbaPlatSpec>;
 
-ox::Error appendBinary(ox::Buffer *binBuff, ox::Buffer *fsBuff, GbaPreloader *pl) noexcept;
+namespace detail {
+// transformations need to be done after the copy to the new FS is complete
+template<typename PlatSpec>
+ox::Error preloadObj(
+		ox::TypeStore *ts,
+		ox::FileSystem *romFs,
+		ox::Preloader<PlatSpec> *pl,
+		ox::CRStringView path) noexcept {
+	// load file
+	oxRequireM(buff, romFs->read(path));
+	oxRequireM(obj, keel::readAsset(ts, buff));
+	if (obj.type()->preloadable) {
+		oxOutf("preloading {}\n", path);
+		// preload
+		oxRequire(a, pl->startAlloc(ox::sizeOf<GbaPlatSpec>(&obj)));
+		const auto err = ox::preload<GbaPlatSpec, decltype(obj)>(pl, &obj);
+		oxReturnError(pl->endAlloc());
+		oxReturnError(err);
+		const keel::PreloadPtr p{.preloadAddr = static_cast<uint32_t>(a)};
+		oxReturnError(ox::writeMC(&p).moveTo(&buff));
+	} else {
+		// strip the Claw header (it is not needed after preloading) and write back out to dest fs
+		oxReturnError(ox::writeMC(&obj).moveTo(&buff));
+	}
+	oxReturnError(romFs->write(path, buff.data(), buff.size()));
+	return {};
+}
+
+// claw file transformations are broken out because path to inode
+// transformations need to be done after the copy to the new FS is complete
+template<typename PlatSpec>
+ox::Error preloadDir(
+		ox::TypeStore *ts,
+		ox::FileSystem *romFs,
+		ox::Preloader<PlatSpec> *pl,
+		ox::CRStringView path) noexcept {
+	// copy
+	oxTracef("pack::preload", "path: {}", path);
+	oxRequire(fileList, romFs->ls(path));
+	for (const auto &name : fileList) {
+		const auto filePath = ox::sfmt("{}{}", path, name);
+		oxRequire(stat, romFs->stat(filePath));
+		if (stat.fileType == ox::FileType::Directory) {
+			const auto dir = ox::sfmt("{}{}/", path, name);
+			oxReturnError(preloadDir(ts, romFs, pl, dir));
+		} else {
+			oxReturnError(preloadObj(ts, romFs, pl, filePath));
+		}
+	}
+	return {};
+}
+
+}
+
+template<typename PlatSpec>
+ox::Error appendBinary(ox::Buffer *binBuff, ox::Buffer *fsBuff, ox::Preloader<PlatSpec> *pl) noexcept {
+	constexpr auto padbin = [](ox::BufferWriter *w, unsigned factor) noexcept -> ox::Error {
+		return w->write(nullptr, factor - w->buff().size() % factor);
+	};
+	constexpr ox::StringView mediaHdr   = "KEEL_MEDIA_HEADER_______________";
+	constexpr ox::StringView preloadHdr = "KEEL_PRELOAD_HEADER_____________";
+	constexpr auto hdrSize = 32u;
+	static_assert(mediaHdr.bytes() == hdrSize);
+	static_assert(preloadHdr.bytes() == hdrSize);
+	ox::BufferWriter w(binBuff);
+	oxReturnError(padbin(&w, hdrSize));
+	oxReturnError(w.write(mediaHdr.data(), mediaHdr.bytes()));
+	oxReturnError(w.write(fsBuff->data(), fsBuff->size()));
+	oxReturnError(padbin(&w, hdrSize));
+	oxReturnError(w.write(preloadHdr.data(), preloadHdr.bytes()));
+	oxReturnError(pl->offsetPtrs(binBuff->size()));
+	const auto &plBuff = pl->buff();
+	oxReturnError(w.write(plBuff.data(), plBuff.size()));
+	return {};
+}
+
+template<typename PlatSpec>
+ox::Error preload(ox::TypeStore *ts, ox::FileSystem *src, ox::Preloader<PlatSpec> *pl) noexcept {
+	oxOut("Preloading\n");
+	return detail::preloadDir(ts, src, pl, "/");
+}
 
 ox::Error pack(keel::Context *ctx, ox::TypeStore *ts, ox::FileSystem *dest) noexcept;
 
-ox::Error preload(ox::TypeStore *ts, ox::FileSystem *src, GbaPreloader *pl) noexcept;
-
 }