diff --git a/build.zig b/build.zig
index d2077be..be6d096 100644
--- a/build.zig
+++ b/build.zig
@@ -129,7 +129,7 @@ pub fn build(b: *std.Build) void {
 
     const mkfs_fat = b.addExecutable(.{
         .name = "mkfs.fat",
-        .target = b.host,
+        .target = b.resolveTargetQuery(.{}),
         .optimize = .ReleaseSafe,
         .root_source_file = b.path("src/mkfs.fat.zig"),
     });
@@ -416,7 +416,7 @@ pub const InitializeDiskStep = struct {
                         var buffer: [64]u8 = undefined;
                         context.appendSliceAssumeCapacity(std.fmt.bufPrint(&buffer, "[{}]", .{part_id}) catch unreachable);
 
-                        try writeDiskImage(b, asking, disk, base + auto_offset, part.size, part.data, context);
+                        try writeDiskImage(b, asking, disk, part.offset orelse base + auto_offset, part.size, part.data, context);
 
                         auto_offset += part.size;
                     }
@@ -524,9 +524,8 @@ pub const InitializeDiskStep = struct {
         }
     }
 
-    fn make(step: *std.Build.Step, progress: std.Progress.Node) !void {
+    fn make(step: *std.Build.Step, _: std.Build.Step.MakeOptions) !void {
         const b = step.owner;
-        _ = progress;
 
         const ids: *InitializeDiskStep = @fieldParentPtr("step", step);
 
@@ -629,11 +628,10 @@ pub const Content = union(enum) {
                             dir.* = try allocator.dupe(u8, dir.*);
                         },
                         .copy_dir, .copy_file => |*cp| {
-                            const cp_new = .{
+                            cp.* = .{
                                 .destination = try allocator.dupe(u8, cp.destination),
                                 .source = cp.source.dupe(b),
                             };
-                            cp.* = cp_new;
                         },
                     }
                 }
@@ -734,6 +732,8 @@ pub const mbr = struct {
         empty = 0x00,
 
         fat12 = 0x01,
+        fat16_small = 0x04,
+        fat16 = 0x06,
         ntfs = 0x07,
 
         fat32_chs = 0x0B,
diff --git a/build.zig.zon b/build.zig.zon
index 7dc6680..2055aba 100644
--- a/build.zig.zon
+++ b/build.zig.zon
@@ -1,10 +1,9 @@
 .{
-    .name = "disk-image-step",
+    .name = "disk_image_step",
     .version = "0.1.0",
     .dependencies = .{
         .zfat = .{
-            .url = "https://github.com/ZigEmbeddedGroup/zfat/archive/68dbbe19258b174fe4f374a91b4cc939019d9fe7.tar.gz",
-            .hash = "1220963601b9bc8dacc422d098368567e5c7b84d21f9ae73067fe3eb9c566aea02fd",
+            .path = "../../libs/zfat"
         },
     },
     .paths = .{
diff --git a/src/shared.zig b/src/shared.zig
index 990aff8..c5dfa31 100644
--- a/src/shared.zig
+++ b/src/shared.zig
@@ -96,7 +96,13 @@ pub fn App(comptime Context: type) type {
 
                         // std.log.info("file(\"{}\", \"{}\")", .{ std.zig.fmtEscapes(src), std.zig.fmtEscapes(dst) });
 
-                        var file = try std.fs.cwd().openFile(src, .{});
+                        var file = std.fs.cwd().openFile(src, .{}) catch |err| switch (err) {
+                            error.FileNotFound => {
+                                std.log.err("file not found: {s}", .{src});
+                                return err;
+                            },
+                            else => return err,
+                        };
                         defer file.close();
 
                         try addFile(file, dst);
@@ -180,7 +186,7 @@ pub fn App(comptime Context: type) type {
                     continue;
                 } else if (std.mem.eql(u8, part, "..")) {
                     // "cd up" is basically just removing the last pushed part
-                    _ = list.popOrNull();
+                    _ = list.pop();
                 } else {
                     // this is an actual "descend"
                     try list.append(part);