android: 16kb alignment updates

diff --git a/contrib/android/Dockerfile b/contrib/android/Dockerfile
index 59b44a8..d1f1c21 100644
--- a/contrib/android/Dockerfile
+++ b/contrib/android/Dockerfile
@@ -25,30 +25,48 @@ ENV LANG="en_US.UTF-8" \
 RUN apt -y update -qq \
     && apt -y install -qq --no-install-recommends --allow-downgrades \
     curl \
+    wget \
     unzip \
     ca-certificates \
+    python3 \
     && apt -y autoremove
 
 
 ENV ANDROID_NDK_HOME="${ANDROID_HOME}/android-ndk"
-ENV ANDROID_NDK_VERSION="23b"
-ENV ANDROID_NDK_HASH="c6e97f9c8cfe5b7be0a9e6c15af8e7a179475b7ded23e2d1c1fa0945d6fb4382"
+#ENV ANDROID_NDK_VERSION="23b"
+#ENV ANDROID_NDK_HASH="c6e97f9c8cfe5b7be0a9e6c15af8e7a179475b7ded23e2d1c1fa0945d6fb4382"
+#ENV ANDROID_NDK_VERSION="27d"
+#ENV ANDROID_NDK_HASH="601246087a682d1944e1e16dd85bc6e49560fe8b6d61255be2829178c8ed15d9"
+ENV ANDROID_NDK_VERSION="23d-canary"
+ENV ANDROID_NDK_HASH="6944ffc20ab018ff4ef6a403048d0a99d50a0630c3eae690c8f803c452f46f3e"
 ENV ANDROID_NDK_HOME_V="${ANDROID_NDK_HOME}-r${ANDROID_NDK_VERSION}"
 
 # get the latest version from https://developer.android.com/ndk/downloads/index.html
 ENV ANDROID_NDK_ARCHIVE="android-ndk-r${ANDROID_NDK_VERSION}-linux.zip"
 ENV ANDROID_NDK_DL_URL="https://dl.google.com/android/repository/${ANDROID_NDK_ARCHIVE}"
 
+# below disabled in favor of CI build download
+
 # download and install Android NDK
-RUN curl --location --progress-bar \
-        "${ANDROID_NDK_DL_URL}" \
-        --output "${ANDROID_NDK_ARCHIVE}" \
-    && echo "${ANDROID_NDK_HASH} ${ANDROID_NDK_ARCHIVE}" | sha256sum -c - \
+#RUN curl --location --progress-bar \
+#        "${ANDROID_NDK_DL_URL}" \
+#        --output "${ANDROID_NDK_ARCHIVE}" \
+#    && echo "${ANDROID_NDK_HASH} ${ANDROID_NDK_ARCHIVE}" | sha256sum -c - \
+#    && mkdir --parents "${ANDROID_NDK_HOME_V}" \
+#    && unzip -q "${ANDROID_NDK_ARCHIVE}" -d "${ANDROID_HOME}" \
+#    && ln -sfn "${ANDROID_NDK_HOME_V}" "${ANDROID_NDK_HOME}" \
+#    && rm -rf "${ANDROID_NDK_ARCHIVE}"
+
+# temporary build using NDK from CI
+ENV CI_REV="12186248"
+ENV CI_NDK_FILE="android-ndk-${CI_REV}-linux-x86_64.zip"
+COPY contrib/android/dl-ndk-ci.sh /tmp/
+RUN /tmp/dl-ndk-ci.sh https://ci.android.com/builds/submitted/${CI_REV}/linux/latest/${CI_NDK_FILE} \
+    && echo "${ANDROID_NDK_HASH} android-ndk-ci-linux-x86_64.zip" | sha256sum -c - \
     && mkdir --parents "${ANDROID_NDK_HOME_V}" \
-    && unzip -q "${ANDROID_NDK_ARCHIVE}" -d "${ANDROID_HOME}" \
+    && unzip -q "android-ndk-ci-linux-x86_64.zip" -d "${ANDROID_HOME}" \
     && ln -sfn "${ANDROID_NDK_HOME_V}" "${ANDROID_NDK_HOME}" \
-    && rm -rf "${ANDROID_NDK_ARCHIVE}"
-
+    && rm -rf "android-ndk-ci-linux-x86_64.zip"
 
 ENV ANDROID_SDK_HOME="${ANDROID_HOME}/android-sdk"
 
@@ -190,8 +208,8 @@ RUN cd /opt \
     && /opt/venv/bin/python3 -m pip install --no-build-isolation --no-dependencies -e .
 
 # install python-for-android
-ENV P4A_CHECKOUT_COMMIT="32a05cdedd41f0f569e9126fdfce23069c36fd9a"
-# ^ from branch electrum_20240930 (note: careful with force-pushing! see #8162)
+ENV P4A_CHECKOUT_COMMIT="003451604321deb1f10d879b63450ec76db4a758"
+# ^ from branch electrum_20240930_android_16kb_page_alignment (note: careful with force-pushing! see #8162)
 RUN cd /opt \
     && git clone https://github.com/spesmilo/python-for-android \
     && cd python-for-android \
diff --git a/contrib/android/barcode_16kb.patch b/contrib/android/barcode_16kb.patch
new file mode 100644
index 0000000..bb9ea20
--- /dev/null
+++ b/contrib/android/barcode_16kb.patch
@@ -0,0 +1,9 @@
+diff --git a/wrappers/aar/zxingcpp/src/main/cpp/CMakeLists.txt b/wrappers/aar/zxingcpp/src/main/cpp/CMakeLists.txt
+index 11332e48..78f514f1 100644
+--- a/wrappers/aar/zxingcpp/src/main/cpp/CMakeLists.txt
++++ b/wrappers/aar/zxingcpp/src/main/cpp/CMakeLists.txt
+@@ -13,3 +13,4 @@ add_subdirectory(${CMAKE_CURRENT_SOURCE_DIR}/../../../../../../core ZXing EXCLUD
+ add_library(zxingcpp_android SHARED ZxingCpp.cpp)
+ 
+ target_link_libraries(zxingcpp_android PRIVATE ZXing::ZXing jnigraphics)
++target_link_options(zxingcpp_android PRIVATE "-Wl,-z,max-page-size=16384")
diff --git a/contrib/android/dl-ndk-ci.sh b/contrib/android/dl-ndk-ci.sh
new file mode 100755
index 0000000..41b1922
--- /dev/null
+++ b/contrib/android/dl-ndk-ci.sh
@@ -0,0 +1,8 @@
+#!/bin/sh
+if [ -z "$1" ]; then
+  echo "missing url"
+  exit 1
+fi
+echo $1
+
+curl $1 | grep "var JSVariables" | python3 -c "import sys; line=sys.stdin.read(); line=line[line.find('{'):-2]; import json; j=json.loads(line); print(j['artifactUrl'])" | wget -i - -O android-ndk-ci-linux-x86_64.zip
diff --git a/contrib/android/make_barcode_scanner.sh b/contrib/android/make_barcode_scanner.sh
index 31f7f83..7c3f70e 100755
--- a/contrib/android/make_barcode_scanner.sh
+++ b/contrib/android/make_barcode_scanner.sh
@@ -65,6 +65,7 @@ else
     info "Building zxing-cpp for $ZXING_CPP_BUILD_ID..."
     ZXING_CPP_DIR="$BUILDDIR/zxing-cpp"
     clone_or_update_repo "$ZXING_CPP_REPO" "$ZXING_CPP_COMMIT_HASH" "$ZXING_CPP_DIR"
+    apply_patch "${CONTRIB_ANDROID}/barcode_16kb.patch" "$ZXING_CPP_DIR"
     cd "$ZXING_CPP_DIR/wrappers/aar"
     chmod +x gradlew
 
diff --git a/contrib/build_tools_util.sh b/contrib/build_tools_util.sh
index aab00ef..0ca8d42 100755
--- a/contrib/build_tools_util.sh
+++ b/contrib/build_tools_util.sh
@@ -72,6 +72,24 @@ clone_or_update_repo() {
     fi
 }
 
+apply_patch() {
+    local patch=$1
+    local path=$2
+
+    if [ -z "$patch" ] || [ -z "$path" ]; then
+        fail "apply_patch: invalid arguments: patch='$patch', path='$path'"
+    fi
+
+    if [ -d "$path" ]; then
+        info "Patching: $patch"
+        cd "$path"
+        patch -p1 <"$patch"
+        cd -
+    else
+        fail "apply_patch: path='$path' not found"
+    fi
+}
+
 # https://github.com/travis-ci/travis-build/blob/master/lib/travis/build/templates/header.sh
 function retry() {
     local result=0