build: fallback to GitHub archive on fetch failure

If git fetch fails for a GitHub branch, download and extract the branch archive tarball. Also tolerate missing .git when reading u-boot/kernel hash.

scripts/compilation.sh

@@ -137,7 +137,11 @@ compile_uboot()
 	# read uboot version
 	local version hash
 	version=$(grab_version "$ubootdir")
-	hash=$(improved_git --git-dir="$ubootdir"/.git rev-parse HEAD)
+	if [[ -d "$ubootdir"/.git ]]; then
+		hash=$(improved_git --git-dir="$ubootdir"/.git rev-parse HEAD 2>/dev/null || true)
+	else
+		hash="nogit"
+	fi
 
 	display_alert "Compiling u-boot" "v$version" "info"
 
@@ -390,7 +394,11 @@ compile_kernel()
 	version=$(grab_version "$kerneldir")
 
 	# read kernel git hash
-	hash=$(improved_git --git-dir="$kerneldir"/.git rev-parse HEAD)
+	if [[ -d "$kerneldir"/.git ]]; then
+		hash=$(improved_git --git-dir="$kerneldir"/.git rev-parse HEAD 2>/dev/null || true)
+	else
+		hash="nogit"
+	fi
 
 	# Apply a series of patches if a series file exists
 	if test -f "${EXTER}"/patch/kernel/${KERNELPATCHDIR}/series.conf; then

scripts/general.sh

@@ -350,6 +350,42 @@ clean_up_git ()
 	git -C $target_dir checkout -qf HEAD
 }
 
+# Fallback for environments where large git pack transfers are unreliable.
+# Downloads a GitHub branch archive and extracts it into the workdir.
+fetch_from_github_archive()
+{
+	local upstream_url=$1
+	local workdir=$2
+	local ref_name=$3
+
+	[[ $upstream_url == https://github.com/* ]] || return 1
+	[[ -n $ref_name ]] || return 1
+
+	local base=${upstream_url%.git}
+	local tar_url="${base}/archive/refs/heads/${ref_name}.tar.gz"
+	local archive_dir="${EXTER}/cache/sources/.github-archives"
+	local tar_path="${archive_dir}/$(basename "${base}")-${ref_name}.tar.gz"
+
+	mkdir -p "${archive_dir}" || return 1
+
+	display_alert "Downloading GitHub archive" "${tar_url}" "wrn"
+	# -c enables resume; keep a cached tarball in EXTER/cache/sources
+	wget -q -c -t 10 --timeout=30 --waitretry=5 -O "${tar_path}" "${tar_url}" || return 1
+
+	display_alert "Extracting archive" "${workdir}" "wrn"
+	mkdir -p "${workdir}" || return 1
+	(
+		cd "${workdir}" || exit 1
+		rm -rf ./* ./.??* 2>/dev/null || true
+	)
+
+	tar -xzf "${tar_path}" -C "${workdir}" --strip-components=1 || return 1
+
+	# Mark as archive-based sources (helps debugging; no functional dependency)
+	echo "${tar_url}" > "${workdir}/.orangepi-source-archive" 2>/dev/null || true
+	return 0
+}
+
 # used : waiter_local_git arg1='value' arg2:'value'
 #		 waiter_local_git \
 #			url='https://github.com/megous/linux' \
@@ -655,7 +691,16 @@ fetch_from_repo()
 			esac
 			fetch_status=$?
 		fi
-		[[ $fetch_status -ne 0 ]] && exit_with_error "Failed to fetch git sources" "${url} ${ref}"
+		if [[ $fetch_status -ne 0 ]]; then
+			# If we're targeting a GitHub branch, fall back to downloading the branch archive.
+			if [[ $ref_type == branch && $upstream_url == https://github.com/* ]]; then
+				display_alert "Git fetch failed; using archive fallback" "${ref_name}" "wrn"
+				# Ensure we don't keep a broken git repository around.
+				rm -rf "${workdir}/.git" 2>/dev/null || true
+				fetch_from_github_archive "${upstream_url}" "${workdir}" "${ref_name}" && return 0
+			fi
+			exit_with_error "Failed to fetch git sources" "${url} ${ref}"
+		fi
 
 		# commit type needs support for older git servers that doesn't support fetching id directly
 		if [[ $ref_type == commit ]]; then