diff --git a/forkop/files/usr/lib/components/action.uc b/forkop/files/usr/lib/components/action.uc
index 993a1507..8cd6c88a 100644
--- a/forkop/files/usr/lib/components/action.uc
+++ b/forkop/files/usr/lib/components/action.uc
@@ -371,7 +371,7 @@ function opkg_package_version_from_list(package_name, output) {
 function available_package_version(package_name) {
     package_name = as_string(package_name);
     if (is_apk())
-        return trim(helper_output_input(command_output_from_args([ "apk", "policy", package_name ]), "updates-apk-policy-version", []));
+        return trim(module_output([ LIB_DIR + "/core/packages.uc", "apk-available-version", package_name ]));
     return opkg_package_version_from_list(package_name, command_output_from_args([ "opkg", "list", package_name ]));
 }
 
@@ -384,12 +384,16 @@ function pkg_install_name_command(package_name) {
         command_from_args([ "opkg", "install", package_name ]) + " </dev/null";
 }
 
-function pkg_install_name_downgrade(package_name) {
+function pkg_install_name_downgrade(package_name, package_version) {
     package_name = as_string(package_name);
     if (is_apk()) {
+        package_version = as_string(package_version);
+        if (package_version == "")
+            return false;
+        let package_spec = package_name + "=" + package_version;
         if (pkg_is_installed(package_name))
-            return command_success(command_from_args([ "apk", "fix", "--reinstall", "--upgrade", package_name ]) + " </dev/null");
-        return command_success(command_from_args([ "apk", "add", package_name ]) + " </dev/null");
+            return command_success(command_from_args([ "apk", "fix", "--reinstall", "--upgrade", package_spec ]) + " </dev/null");
+        return command_success(command_from_args([ "apk", "add", package_spec ]) + " </dev/null");
     }
 
     return command_success(command_from_args([ "opkg", "install", "--force-overwrite", "--force-reinstall", "--force-downgrade", package_name ]) + " </dev/null") ||
@@ -1150,7 +1154,8 @@ function restore_file_backup(target_path, backup_path) {
 }
 
 function restore_sing_box_service_from_marker(marker) {
-    if (as_string(marker) == "extended-compressed")
+    if (as_string(marker) == "extended-compressed" ||
+        (!file_exists("/etc/init.d/sing-box") && file_nonempty("/usr/bin/sing-box")))
         return install_managed_sing_box_service_script();
     remove_managed_sing_box_service_script();
     return true;
@@ -1265,24 +1270,24 @@ function restore_sing_box_extended_package_variant() {
     return true;
 }
 
-function replace_sing_box_package_variant(target_package, conflict_package) {
+function replace_sing_box_package_variant(target_package, conflict_package, target_version) {
     prepare_sing_box_package_service_install();
     if ((as_string(conflict_package) == "" || !pkg_is_installed(conflict_package)) &&
         (target_package == "sing-box-extended" || !pkg_is_installed("sing-box-extended")))
-        return pkg_install_name_downgrade(target_package);
+        return pkg_install_name_downgrade(target_package, target_version);
 
     if (target_package != "sing-box-extended" && !pkg_remove_sing_box_conflict("sing-box-extended"))
         return false;
     if (as_string(conflict_package) != "" && !pkg_remove_sing_box_conflict(conflict_package))
         return false;
-    return pkg_install_name_downgrade(target_package);
+    return pkg_install_name_downgrade(target_package, target_version);
 }
 
 function restore_sing_box_package_variant(previous_variant) {
     if (previous_variant == "tiny")
-        return replace_sing_box_package_variant("sing-box-tiny", "sing-box");
+        return replace_sing_box_package_variant("sing-box-tiny", "sing-box", available_package_version("sing-box-tiny"));
     if (previous_variant == "stable")
-        return replace_sing_box_package_variant("sing-box", "sing-box-tiny");
+        return replace_sing_box_package_variant("sing-box", "sing-box-tiny", available_package_version("sing-box"));
     if (previous_variant == "extended")
         return restore_sing_box_extended_package_variant();
     if (previous_variant == "not-installed") {
@@ -1304,8 +1309,10 @@ function restore_sing_box_install_backup(previous_variant, backup_binary) {
     if (sing_box_variant_is_package_managed(previous_variant)) {
         if (restore_sing_box_package_variant(previous_variant))
             return true;
-        if (as_string(backup_binary) != "")
-            restore_sing_box_backup(backup_binary);
+        if (as_string(backup_binary) != "" && restore_sing_box_backup(backup_binary)) {
+            updates_log("Package rollback failed; restored the previous sing-box binary backup", "warn");
+            return true;
+        }
         return false;
     }
 
@@ -1708,7 +1715,7 @@ function install_package_sing_box(action, tiny) {
     }
 
     if (!run_logged("Installing " + label + " package", "sh -c " + shell_quote("exit 0")) ||
-        !replace_sing_box_package_variant(package_name, conflict))
+        !replace_sing_box_package_variant(package_name, conflict, latest_version))
         fail_package_sing_box_install(action, tiny, "package installation failed", current_version, latest_version,
             package_name, previous_variant, backup_binary, backup_cronet, previous_marker, previous_version_state, cronet_touched);
 
diff --git a/forkop/files/usr/lib/core/packages.uc b/forkop/files/usr/lib/core/packages.uc
index c94da186..0ee9ac1f 100644
--- a/forkop/files/usr/lib/core/packages.uc
+++ b/forkop/files/usr/lib/core/packages.uc
@@ -102,6 +102,16 @@ function apk_version(package_name) {
     return apk_info_version(package_name, command_output([ "apk", "info", "-v", package_name ]));
 }
 
+function apk_available_version(package_name) {
+    package_name = as_string(package_name);
+    if (!command_exists("apk"))
+        return "";
+    return apk_manifest_version(
+        package_name,
+        command_output([ "apk", "list", "--available", "--manifest", package_name ])
+    );
+}
+
 function opkg_version(package_name) {
     package_name = as_string(package_name);
     if (!command_exists("opkg"))
@@ -133,9 +143,11 @@ else if (mode == "version")
     print(version(ARGV[1]), "\n");
 else if (mode == "apk-version")
     print(apk_version(ARGV[1]), "\n");
+else if (mode == "apk-available-version")
+    print(apk_available_version(ARGV[1]), "\n");
 else if (mode == "opkg-version")
     print(opkg_version(ARGV[1]), "\n");
 else {
-    warn("Usage: core/packages.uc <installed|apk-installed|opkg-installed|version|apk-version|opkg-version> <package>\n");
+    warn("Usage: core/packages.uc <installed|apk-installed|opkg-installed|version|apk-version|apk-available-version|opkg-version> <package>\n");
     exit(1);
 }
diff --git a/tests/components_updater_job.sh b/tests/components_updater_job.sh
index 3a438920..3e0d239e 100644
--- a/tests/components_updater_job.sh
+++ b/tests/components_updater_job.sh
@@ -101,6 +101,12 @@ grep -Fq 'forkop_status_running_with_timeout()' "$ACTION_UC" ||
   fail "components/action.uc must use bounded Forkop status checks for component actions"
 grep -Fq 'restore_sing_box_after_failed_package_install' "$ACTION_UC" ||
   fail "stable and tiny sing-box package installs must restore the previous variant after validation failures"
+grep -Fq 'let package_spec = package_name + "=" + package_version;' "$ACTION_UC" ||
+  fail "APK sing-box installs must pin the concrete package version instead of selecting a provider"
+grep -Fq 'Package rollback failed; restored the previous sing-box binary backup' "$ACTION_UC" ||
+  fail "package rollback must accept a successfully restored binary backup"
+grep -Fq '!file_exists("/etc/init.d/sing-box") && file_nonempty("/usr/bin/sing-box")' "$ACTION_UC" ||
+  fail "binary rollback must restore a managed sing-box service when the package script is missing"
 grep -Fq 'fail_package_sing_box_install(action, tiny, "package was installed, but sing-box binary is not available"' "$ACTION_UC" ||
   fail "stable and tiny sing-box binary validation failures must use transactional rollback"
 grep -Fq 'fail_package_sing_box_install(action, tiny, "was installed, but Forkop did not start cleanly"' "$ACTION_UC" ||
@@ -184,6 +190,12 @@ if (mode == "opkg-version")
   exit(0);
 if (mode == "opkg-installed")
   exit(1);
+if (mode == "apk-available-version") {
+  print("1.2.3-r1\n");
+  exit(0);
+}
+if (mode == "apk-version")
+  exit(0);
 exit(1);
 UCODE
 cat >"$package_runtime_lib/singbox/runtime.uc" <<'UCODE'
@@ -253,6 +265,38 @@ if (secondList <= update) fail('stable sing-box version must be resolved again a
 if (install <= secondList) fail('stable sing-box install must happen after post-update version resolve');
 NODE
 
+cat >"$package_runtime_bin/apk" <<'SH'
+#!/usr/bin/env sh
+set -eu
+printf 'apk %s\n' "$*" >>"${FAKE_APK_LOG:?}"
+case "${1:-}" in
+  info)
+    exit 1
+    ;;
+  update|add|fix|del)
+    exit 0
+    ;;
+  *)
+    exit 1
+    ;;
+esac
+SH
+chmod +x "$package_runtime_bin/apk"
+set +e
+PATH="$package_runtime_bin:$PATH" \
+FORKOP_LIB="$package_runtime_lib" \
+FORKOP_RUNTIME_STATE_DIR="$WORK_DIR/apk-package-runtime" \
+FORKOP_BIN="$WORK_DIR/missing-forkop" \
+FORKOP_SERVICE_INIT="$WORK_DIR/missing-init" \
+FAKE_APK_LOG="$WORK_DIR/apk.log" \
+ucode -L "$package_runtime_lib" "$ACTION_UC" component-action sing_box install_stable >/dev/null
+set -e
+grep -Fxq 'apk add sing-box=1.2.3-r1' "$WORK_DIR/apk.log" ||
+  fail "APK stable action must request the exact sing-box package version"
+if grep -Fxq 'apk add sing-box' "$WORK_DIR/apk.log"; then
+  fail "APK stable action must not use the provider-selecting unversioned package name"
+fi
+
 release_json="$(cat <<'JSON'
 {
   "tag_name": "1.2.3",
diff --git a/tests/helpers_owner.sh b/tests/helpers_owner.sh
index e358299c..2e0d85ed 100644
--- a/tests/helpers_owner.sh
+++ b/tests/helpers_owner.sh
@@ -94,6 +94,24 @@ if ucode -L "$FORKOP_LIB" "$PACKAGES_UC" installed forkop-definitely-missing >/d
   fail "missing package must not be reported installed"
 fi
 
+mkdir -p "$WORK_DIR/apk-bin"
+cat >"$WORK_DIR/apk-bin/apk" <<'SH'
+#!/usr/bin/env sh
+if [ "$1 $2 $3 $4" = "list --available --manifest sing-box" ]; then
+  printf '%s\n' \
+    'P:sing-box-extended' \
+    'V:9.9.9-r1' \
+    'p:sing-box' \
+    'P:sing-box' \
+    'V:1.2.3-r1'
+  exit 0
+fi
+exit 1
+SH
+chmod +x "$WORK_DIR/apk-bin/apk"
+[ "$(PATH="$WORK_DIR/apk-bin:$PATH" ucode -L "$FORKOP_LIB" "$PACKAGES_UC" apk-available-version sing-box)" = "1.2.3-r1" ] ||
+  fail "APK available version lookup must select the exact package name, not a higher-priority provider"
+
 mark_hex="$(ucode -L "$FORKOP_LIB" "$RULES_UC" mark-hex 0x01000000 2)"
 [ "$mark_hex" = "0x01000002" ] ||
   fail "providers/rules.uc mark math changed"