diff --git a/.tangled/workflows/ci.yml b/.tangled/workflows/ci.yml
index 321fb05..dcf8e73 100644
--- a/.tangled/workflows/ci.yml
+++ b/.tangled/workflows/ci.yml
@@ -23,3 +23,7 @@ steps:
   - name: run tests
     command: |
       /tangled/workspace/.zig/zig build test --summary all
+
+  - name: compile tests for 32-bit arm (no 64-bit atomics)
+    command: |
+      /tangled/workspace/.zig/zig build test -Dtarget=arm-linux-musleabihf -Dcpu=arm1176jzf_s --summary all
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 95f34f0..88eea0b 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,19 @@
 # changelog
 
+## 0.4.4
+
+- **fix**: zat compiles for 32-bit targets without native 64-bit atomics (ARMv6, e.g. a
+  Raspberry Pi 1 running zds). the three `std.atomic.Value(u64)` counters — the jetstream and
+  firehose `frames_this_connection` idle detectors and the xrpc `StreamProgress.bytes` stall
+  detector — only ever ask "did this change since last tick", so they are `usize` now. the
+  `cbor.Value`/`MapEntry` size asserts pin 64-bit layouts only, and `Cid.digest()` rejects a
+  varint digest length that does not fit `usize` instead of failing to coerce.
+- **ci**: compile the test module for `arm-linux-musleabihf` (`arm1176jzf_s`) on every push so
+  32-bit support cannot regress silently; `skip_foreign_checks` keeps the run step from trying
+  to execute the foreign binary.
+- **docs**: tidy stray root docs, refresh the downstream list.
+- **test**: cover pruning an empty node stranded as a left child.
+
 ## 0.4.3
 
 - **fix**: `Mst.collectBlocks` now emits the block for an empty node instead of
diff --git a/build.zig b/build.zig
index 2ea8d84..b063c25 100644
--- a/build.zig
+++ b/build.zig
@@ -67,6 +67,7 @@ pub fn build(b: *std.Build) void {
     }
 
     const run_tests = b.addRunArtifact(tests);
+    run_tests.skip_foreign_checks = true;
 
     const test_step = b.step("test", "run unit tests");
     test_step.dependOn(&run_tests.step);
diff --git a/build.zig.zon b/build.zig.zon
index d547021..218e577 100644
--- a/build.zig.zon
+++ b/build.zig.zon
@@ -1,6 +1,6 @@
 .{
     .name = .zat,
-    .version = "0.4.3",
+    .version = "0.4.4",
     .fingerprint = 0x8da9db57ee82fbe4,
     .minimum_zig_version = "0.16.0-dev.3070+b22eb176b",
     .dependencies = .{
diff --git a/src/internal/repo/cbor.zig b/src/internal/repo/cbor.zig
index 29d9ff3..a6ab371 100644
--- a/src/internal/repo/cbor.zig
+++ b/src/internal/repo/cbor.zig
@@ -130,10 +130,13 @@ pub const Value = union(enum) {
         };
     }
 
-    // verify the Value union stayed slim after Cid optimization (was ~64, now 24)
+    // verify the Value union stayed slim after Cid optimization (was ~64, now 24).
+    // sizes are for 64-bit pointers; 32-bit targets are smaller and not pinned.
     comptime {
-        std.debug.assert(@sizeOf(Value) == 24);
-        std.debug.assert(@sizeOf(MapEntry) == 40);
+        if (@sizeOf(usize) == 8) {
+            std.debug.assert(@sizeOf(Value) == 24);
+            std.debug.assert(@sizeOf(MapEntry) == 40);
+        }
     }
 };
 
@@ -196,7 +199,7 @@ pub const Cid = struct {
         _ = readUvarint(self.raw, &pos) orelse return null; // version
         _ = readUvarint(self.raw, &pos) orelse return null; // codec
         _ = readUvarint(self.raw, &pos) orelse return null; // hash_fn
-        const digest_len = readUvarint(self.raw, &pos) orelse return null;
+        const digest_len = std.math.cast(usize, readUvarint(self.raw, &pos) orelse return null) orelse return null;
         if (pos + digest_len > self.raw.len) return null;
         return self.raw[pos..][0..digest_len];
     }
diff --git a/src/internal/streaming/firehose.zig b/src/internal/streaming/firehose.zig
index 534a1c3..6353891 100644
--- a/src/internal/streaming/firehose.zig
+++ b/src/internal/streaming/firehose.zig
@@ -730,7 +730,7 @@ pub const FirehoseClient = struct {
     connected_this_attempt: bool = false,
     /// frames delivered on the current connection; written by the reader
     /// task and read by the idle watchdog, hence atomic.
-    frames_this_connection: std.atomic.Value(u64) = .init(0),
+    frames_this_connection: std.atomic.Value(usize) = .init(0),
 
     pub fn init(io: Io, allocator: Allocator, options: Options) FirehoseClient {
         return .{
@@ -903,7 +903,7 @@ pub const FirehoseClient = struct {
             var future = try self.io.concurrent(Reader.run, .{ self.io, &client, &ws_handler, &done, &read_err });
             var joined = false;
             defer if (!joined) future.cancel(self.io);
-            var last_frames: u64 = 0;
+            var last_frames: usize = 0;
             while (true) {
                 done.waitTimeout(self.io, .{ .duration = .{ .raw = Io.Duration.fromMilliseconds(@intCast(timeout_ms)), .clock = .awake } }) catch |err| switch (err) {
                     error.Timeout => {
diff --git a/src/internal/streaming/jetstream.zig b/src/internal/streaming/jetstream.zig
index f4b2399..e2496ff 100644
--- a/src/internal/streaming/jetstream.zig
+++ b/src/internal/streaming/jetstream.zig
@@ -152,7 +152,7 @@ pub const JetstreamClient = struct {
     /// raw frames on the current connection; written by the reader task and
     /// read by the idle watchdog, hence atomic (events_this_connection stays
     /// plain: it is only read after the reader task is joined).
-    frames_this_connection: std.atomic.Value(u64) = .init(0),
+    frames_this_connection: std.atomic.Value(usize) = .init(0),
 
     pub fn init(io: Io, allocator: Allocator, options: Options) JetstreamClient {
         return .{
@@ -283,7 +283,7 @@ pub const JetstreamClient = struct {
             var future = try self.io.concurrent(Reader.run, .{ self.io, &client, &ws_handler, &done, &read_err });
             var joined = false;
             defer if (!joined) future.cancel(self.io);
-            var last_frames: u64 = 0;
+            var last_frames: usize = 0;
             while (true) {
                 done.waitTimeout(self.io, .{ .duration = .{ .raw = Io.Duration.fromMilliseconds(@intCast(timeout_ms)), .clock = .awake } }) catch |err| switch (err) {
                     error.Timeout => {
diff --git a/src/internal/xrpc/transport.zig b/src/internal/xrpc/transport.zig
index d40a820..cbd9e01 100644
--- a/src/internal/xrpc/transport.zig
+++ b/src/internal/xrpc/transport.zig
@@ -416,7 +416,7 @@ fn parseHeaderInt(value: []const u8) ?u64 {
 }
 
 const StreamProgress = struct {
-    bytes: std.atomic.Value(u64) = .init(0),
+    bytes: std.atomic.Value(usize) = .init(0),
     done: std.atomic.Value(bool) = .init(false),
 };
 
@@ -467,7 +467,7 @@ fn streamResponseBody(
     const tick_ns: u64 = 100 * std.time.ns_per_ms;
     var idle_ns: u64 = 0;
     var elapsed_ns: u64 = 0;
-    var last_bytes: u64 = 0;
+    var last_bytes: usize = 0;
 
     while (!progress.done.load(.acquire)) {
         std.Io.Clock.Duration.sleep(