diff --git a/home/termux.nix b/home/termux.nix
index 8fce3b3..cfa3d92 100644
--- a/home/termux.nix
+++ b/home/termux.nix
@@ -62,10 +62,6 @@
       ".ssh/authorized_keys".text = ''
         ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIKduJia+unaQQdN6X5syaHvnpIutO+yZwvfiCP4qKQ/P
       '';
-      # nix-on-droid's session-init adds ~/.nix-defexpr/channels to NIX_PATH
-      # unconditionally; nix warns about the missing dir on every invocation.
-      # Making it exist silences the warning.
-      ".nix-defexpr/channels/nixpkgs/.keep".text = "";
     };
   };
   programs = {
diff --git a/modules/termux/default.nix b/modules/termux/default.nix
index b182cb8..6cbd77b 100644
--- a/modules/termux/default.nix
+++ b/modules/termux/default.nix
@@ -49,6 +49,17 @@ in
     fi
   '';
 
+  # nix-on-droid's session-init adds ~/.nix-defexpr/channels to NIX_PATH
+  # unconditionally; nix warns about the missing dir on every invocation.
+  # Making it exist silences the warning. Must be done in activation (not
+  # home-manager): ~/.nix-defexpr/channels is a symlink into
+  # ~/.local/state/nix/profiles/channels, which home-manager cannot link
+  # into.
+  build.activation.nixdefexpr = ''
+    $DRY_RUN_CMD mkdir -p "${config.user.home}/.nix-defexpr/channels/nixpkgs"
+    $DRY_RUN_CMD touch "${config.user.home}/.nix-defexpr/channels/nixpkgs/.keep"
+  '';
+
   # runit service tree: ~/service/<name>/{run,log/run}. run/ and log/run are
   # symlinks into the nix store (read-only is fine; runsvdir writes only to
   # the <name>/supervise dirs). /etc/service is symlinked for `sv status`.