Try Albin's rbit PR...

Author: oscarbenjamin

bin/build_dependencies_unix.sh

@@ -278,9 +278,12 @@ echo "           building Flint"
 echo --------------------------------------------
 echo
 
-curl -O -L https://github.com/flintlib/flint/releases/download/v$FLINTVER/flint-$FLINTVER.tar.gz
-tar xf flint-$FLINTVER.tar.gz
-cd flint-$FLINTVER
+#curl -O -L https://github.com/flintlib/flint/releases/download/v$FLINTVER/flint-$FLINTVER.tar.gz
+#tar xf flint-$FLINTVER.tar.gz
+#cd flint-$FLINTVER
+git clone https://github.com/albinahlback/flint.git
+cd flint
+git checkout rbit
   ./bootstrap.sh
   # --host=$HOST_ARG\ # host is ignored
   # --enable-arch works on 3.1.3p1, not available  on HEAD

pyproject.toml

@@ -89,7 +89,7 @@ skip = "*-win32 *-manylinux_i686 *-musllinux_*"
 # free-threaded-support = true
 
 manylinux-x86_64-image = "manylinux2014"
-manylinux-aarch64-image = "manylinux_2_28"
+manylinux-aarch64-image = "manylinux2014"
 manylinux-i686-image = "manylinux2014"
 test-command = "python -c \"import flint; print(str(flint.fmpz(2)))\""