diff --git a/README.md b/README.md
index fb7e4990..868d8ff6 100644
--- a/README.md
+++ b/README.md
@@ -179,6 +179,10 @@ Root changes the device security model and can introduce compatibility breakage
 
 ModOS defaults to the official `topjohnwu/Magisk` repository. The source remains configurable through `MAGISK[REPOSITORY]` in `env.toml`, but alternate Magisk forks are opt-in rather than part of the GrapheneOS build contract. If you use Zygisk Next for GrapheneOS compatibility, install and manage it separately from the OTA build. Magisk/Zygisk behavior can change across releases, so rooted builds should be revalidated after ROM, Magisk, or Zygisk changes.
 
+ModOS currently pins **official Magisk v30.7** as its avbroot compatibility baseline. This mirrors the current rooted-GrapheneOS reference pairing with avbroot 3.34.1. avbroot 3.34.0 and newer explicitly recognize Magisk 31000, but parser/patch-format support is not the same as target-device runtime validation, so ModOS does not automatically advance to the highest Magisk tag. Override `MAGISK_VERSION` only for an intentional compatibility test.
+
+With avbroot, Magisk is not updated using the app's normal **Direct install** path. Magisk version changes must be made by repatching/re-signing the OTA and installing that OTA. The manager's **Additional setup / Environment fix** is a separate runtime-environment step and does not replace OTA repatching.
+
 A Magisk-patched OTA is only the boot-image half of a working Magisk installation. On a clean install, after a data wipe, or whenever Magisk reports that additional setup is required, install/open the **matching Magisk manager APK**, accept **Additional setup / Environment fix**, and allow the device to reboot. That step provisions the runtime binaries (including `su`) under `/data/adb/magisk`; those files are device state and cannot be embedded in or verified from an OTA image.
 
 After that reboot, verify runtime root on the actual device:
diff --git a/env.toml b/env.toml
index 7fc53059..e576b6e6 100644
--- a/env.toml
+++ b/env.toml
@@ -12,6 +12,9 @@ ROM_FAMILY = "grapheneos"
 # 'MAGISK[REPOSITORY]' = "topjohnwu/Magisk"
 
 [build]
+# Magisk is pinned deliberately for avbroot compatibility. Bump only after
+# reviewing avbroot support and validating the target device/runtime path.
+# MAGISK_VERSION = "v30.7"
 # Legacy single-output switch: false = rootless, true = Magisk.
 # ROOT = true
 # Optional override: "rootless", "magisk", or "both".
diff --git a/src/ci/selection_variant.sh b/src/ci/selection_variant.sh
index df710817..5debe9f2 100755
--- a/src/ci/selection_variant.sh
+++ b/src/ci/selection_variant.sh
@@ -17,6 +17,7 @@ function selection_variant_manifest() {
     SELECTION_ROOT
     SELECTION_MAGISK_PREINIT
     SELECTION_MAGISK_REPOSITORY
+    SELECTION_MAGISK_VERSION
     SELECTION_DEBUG
     SELECTION_COMPATIBLE_SEPOLICY
     SELECTION_CLEAR_VBMETA_FLAGS
@@ -103,7 +104,13 @@ function selection_variant_manifest() {
       echo "Error: rooted selection identity has an invalid Magisk repository." >&2
       return 1
     fi
-    printf '%s\n' "magisk_repository=${SELECTION_MAGISK_REPOSITORY}"
+    if [[ ! "${SELECTION_MAGISK_VERSION}" =~ ^v[0-9]+([.][0-9A-Za-z_-]+)*$ ]]; then
+      echo "Error: rooted selection identity has an invalid Magisk version." >&2
+      return 1
+    fi
+    printf '%s\n' \
+      "magisk_repository=${SELECTION_MAGISK_REPOSITORY}" \
+      "magisk_version=${SELECTION_MAGISK_VERSION}"
   fi
 
   if [[ "${SELECTION_BOOT_ANIMATION}" == 'true' ]]; then
diff --git a/src/config_schema.sh b/src/config_schema.sh
index 10584759..bbfee73d 100644
--- a/src/config_schema.sh
+++ b/src/config_schema.sh
@@ -78,6 +78,8 @@ _config_schema_define update_channel 'GRAPHENEOS[UPDATE_CHANNEL]' device string
   GRAPHENEOS array UPDATE_CHANNEL GRAPHENEOS_UPDATE_CHANNEL '' true existing-or-default
 _config_schema_define magisk_repository 'MAGISK[REPOSITORY]' device string \
   MAGISK array REPOSITORY '' topjohnwu/Magisk false caller-or-default
+_config_schema_define magisk_version MAGISK_VERSION build string \
+  VERSION array MAGISK MAGISK_VERSION v30.7 true caller-or-existing-or-default
 _config_schema_define afsr 'ADDITIONALS[AFSR]' build boolean \
   ADDITIONALS array AFSR ADDITIONALS_AFSR true true caller-or-existing-or-default
 _config_schema_define alterinstaller 'ADDITIONALS[ALTERINSTALLER]' build boolean \
diff --git a/src/fetcher.sh b/src/fetcher.sh
index 1b3c5f8c..aad429ff 100755
--- a/src/fetcher.sh
+++ b/src/fetcher.sh
@@ -8,17 +8,21 @@ source src/declarations.sh
 source src/rom_profiles.sh
 source src/ota_providers.sh
 
-# Fetch the latest version of GrapheneOS and Magisk and sets up the OTA URL
+# Resolve the ROM version plus the configured Magisk compatibility version
 function get_latest_version() {
-  local latest_magisk_version=$(
-    git ls-remote --tags "${DOMAIN}/${MAGISK[REPOSITORY]}.git" |
-      awk -F'\t' '{print $2}' |
-      grep -E 'refs/tags/' |
-      grep -v '\^{}$' |
-      sed 's/refs\/tags\///' |
-      sort -V |
-      tail -n1
-  )
+  local selected_magisk_version="${VERSION[MAGISK]:-}"
+
+  if [[ -z "${selected_magisk_version}" ]]; then
+    selected_magisk_version=$(
+      git ls-remote --tags "${DOMAIN}/${MAGISK[REPOSITORY]}.git" |
+        awk -F'\t' '{print $2}' |
+        grep -E 'refs/tags/' |
+        grep -v '\^{}$' |
+        sed 's/refs\/tags\///' |
+        sort -V |
+        tail -n1
+    )
+  fi
 
   resolve_rom_profile || return 1
 
@@ -30,12 +34,16 @@ function get_latest_version() {
   fetch_rom_ota_metadata || return 1
   echo -e "${ROM_FAMILY} OTA target: \`${GRAPHENEOS[OTA_TARGET]}\`\nOTA URL: ${GRAPHENEOS[OTA_URL]}\n"
 
-  if [[ -z "${latest_magisk_version}" ]]; then
-    echo -e "Failed to get the latest Magisk version."
+  if [[ -z "${selected_magisk_version}" ]]; then
+    echo -e "Failed to resolve the Magisk version."
     exit 1
-  else
-    VERSION[MAGISK]="${latest_magisk_version}"
   fi
+  if [[ ! "${selected_magisk_version}" =~ ^v[0-9]+([.][0-9A-Za-z_-]+)*$ ]]; then
+    echo -e "Invalid Magisk version tag: ${selected_magisk_version}"
+    exit 1
+  fi
+
+  VERSION[MAGISK]="${selected_magisk_version}"
 }
 
 # Getter function to download the magisk, modules, signatures and tools
diff --git a/src/rom_profiles.sh b/src/rom_profiles.sh
index 3ed3d523..ea555680 100644
--- a/src/rom_profiles.sh
+++ b/src/rom_profiles.sh
@@ -151,6 +151,7 @@ function module_selection_fingerprint() {
   local profile_digest="disabled"
   local magisk_preinit="disabled"
   local magisk_repository="disabled"
+  local magisk_version="disabled"
   local boot_animation_digest="disabled"
   local entry
   local -a module_entries=(
@@ -186,6 +187,7 @@ function module_selection_fingerprint() {
   if [[ "${ADDITIONALS[ROOT]}" == 'true' ]]; then
     magisk_preinit="${MAGISK[PREINIT]}"
     magisk_repository="${MAGISK[REPOSITORY]}"
+    magisk_version="${VERSION[MAGISK]}"
     if [[ ! "${magisk_preinit}" =~ ^[A-Za-z0-9._-]+$ ]]; then
       echo "Error: rooted profiles require a canonical Magisk preinit device." >&2
       return 1
@@ -194,6 +196,10 @@ function module_selection_fingerprint() {
       echo "Error: rooted profiles require a canonical Magisk repository." >&2
       return 1
     fi
+    if [[ ! "${magisk_version}" =~ ^v[0-9]+([.][0-9A-Za-z_-]+)*$ ]]; then
+      echo "Error: rooted profiles require a canonical Magisk version tag." >&2
+      return 1
+    fi
   fi
 
   if [[ "${ADDITIONALS[FDROID_PRIVILEGED_EXTENSION]}" == 'true' ]]; then
@@ -214,6 +220,7 @@ function module_selection_fingerprint() {
   SELECTION_ROOT="${ADDITIONALS[ROOT]}"
   SELECTION_MAGISK_PREINIT="${magisk_preinit}"
   SELECTION_MAGISK_REPOSITORY="${magisk_repository}"
+  SELECTION_MAGISK_VERSION="${magisk_version}"
   SELECTION_DEBUG="${ADDITIONALS[DEBUG]}"
   SELECTION_COMPATIBLE_SEPOLICY="${ADDITIONALS[MAS_COMPATIBLE_SEPOLICY]}"
   SELECTION_CLEAR_VBMETA_FLAGS="${ROM_PROFILE[CLEAR_VBMETA_FLAGS]}"
diff --git a/tests/provider_acquisition_test.sh b/tests/provider_acquisition_test.sh
index bd32516c..ca2dda47 100644
--- a/tests/provider_acquisition_test.sh
+++ b/tests/provider_acquisition_test.sh
@@ -43,6 +43,24 @@ reset_acquisition_fixture() {
   ADDITIONALS_MAS_COMPATIBLE_SEPOLICY=""
 }
 
+test_pinned_magisk_version_skips_tag_discovery() (
+  reset_acquisition_fixture
+  ROM_FAMILY="grapheneos"
+  DEVICE_NAME="shiba"
+  VERSION[MAGISK]="v30.7"
+
+  git() { fail "pinned Magisk version unexpectedly queried git tags"; }
+  curl() {
+    local url="${!#}"
+    [[ "${url}" == "https://releases.grapheneos.org/shiba-stable" ]] ||
+      fail "unexpected GrapheneOS metadata URL: ${url}"
+    printf '%s\n' '2026071700 1784260800'
+  }
+
+  get_latest_version >/dev/null
+  assert_equals "v30.7" "${VERSION[MAGISK]}" "pinned Magisk version"
+)
+
 test_grapheneos_text_metadata() (
   reset_acquisition_fixture
   ROM_FAMILY="grapheneos"
@@ -200,6 +218,7 @@ test_unsafe_lineageos_metadata_fails_closed() (
   fi
 )
 
+test_pinned_magisk_version_skips_tag_discovery
 test_grapheneos_text_metadata
 test_lineageos_v2_metadata
 test_lineageos_digest_verification
diff --git a/tests/rom_contract_test.sh b/tests/rom_contract_test.sh
index dd97d3e4..a9522290 100644
--- a/tests/rom_contract_test.sh
+++ b/tests/rom_contract_test.sh
@@ -77,10 +77,12 @@ test_profiles_are_stable() {
     https://download.lineageos.org/api/v2
 }
 
-test_magisk_repository_default() (
+test_magisk_compatibility_defaults() (
   load_contract
   assert_equals "topjohnwu/Magisk" "${MAGISK[REPOSITORY]}" \
     "default Magisk repository"
+  assert_equals "v30.7" "${VERSION[MAGISK]}" \
+    "default Magisk compatibility version"
 )
 
 test_unknown_rom_fails_closed() (
@@ -132,7 +134,7 @@ fingerprint() {
 test_selection_fingerprint() (
   local baseline repeated afsr_on afsr_off root_changed rom_changed module_changed
   local boot_changed second_boot_changed fingerprint_input
-  local rootless_repo_changed rooted_repo_changed
+  local rootless_repo_changed rooted_repo_changed rooted_version_changed
 
   load_contract
   set_selection_fixture
@@ -180,6 +182,12 @@ test_selection_fingerprint() (
     fail "Magisk repository selection did not change the rooted fingerprint"
   MAGISK[REPOSITORY]="topjohnwu/Magisk"
 
+  VERSION[MAGISK]="v30.6"
+  rooted_version_changed="$(fingerprint)"
+  [[ "${rooted_version_changed}" != "${root_changed}" ]] ||
+    fail "Magisk version selection did not change the rooted fingerprint"
+  VERSION[MAGISK]="v30.7"
+
   MAGISK[PREINIT]="sda47"
   local preinit_changed
   preinit_changed="$(fingerprint)"
@@ -282,7 +290,7 @@ test_output_policy() (
 )
 
 test_profiles_are_stable
-test_magisk_repository_default
+test_magisk_compatibility_defaults
 test_unknown_rom_fails_closed
 test_invalid_compatible_sepolicy_fails_closed
 test_selection_fingerprint
diff --git a/tests/upstream_integration_test.sh b/tests/upstream_integration_test.sh
index 68250339..eb6d905b 100644
--- a/tests/upstream_integration_test.sh
+++ b/tests/upstream_integration_test.sh
@@ -13,6 +13,7 @@ grep -Fq 'VERSION[CUSTOTA]="${VERSION[CUSTOTA]:-6.5}"' src/declarations.sh || fa
 grep -Fq 'VERSION[AVBROOT_SETUP]="634e6185cf70ea3ec9229ae957ddf2304f52e9e8"' src/declarations.sh || fail "maintained helper pin is unexpected"
 grep -Fq '"version": "2.0.0"' locks/executable-tools-v1.json || fail "AFSR 2.0 lock entry is missing"
 grep -Fq "topjohnwu/Magisk" src/config_schema.sh || fail "official Magisk default is missing"
+grep -Fq "VERSION array MAGISK MAGISK_VERSION v30.7" src/config_schema.sh || fail "Magisk v30.7 compatibility pin is missing"
 if grep -Fq "pixincreate/Magisk" src/config_schema.sh; then
   fail "pixincreate Magisk must remain opt-in rather than the default"
 fi