diff --git a/pkgs/nomarchy-install/nomarchy-install.sh b/pkgs/nomarchy-install/nomarchy-install.sh
index b7ed0a6..8bdc79f 100644
--- a/pkgs/nomarchy-install/nomarchy-install.sh
+++ b/pkgs/nomarchy-install/nomarchy-install.sh
@@ -496,13 +496,9 @@ fi
         commit -qm "Initial Nomarchy configuration"
 )
 
-# The user must own their flake — libgit2 refuses repositories owned by
-# someone else, which breaks `home-manager switch` (and theme switching)
-# outright. The first normal NixOS user is always 1000:users(100); the
-# account doesn't exist in the target yet, so numeric ids it is.
-chown -R 1000:100 "$FLAKE_DIR"
 # The templates come out of the nix store mode 0444 and cp preserves
-# that — without this the user owns home.nix but can't edit it.
+# that — without this the user can't edit home.nix after they own it.
+# Ownership is applied after nixos-install (real uid/gid; see below).
 chmod -R u+w "$FLAKE_DIR"
 
 # /etc/nixos on the installed system points at the user-owned flake.
@@ -554,6 +550,17 @@ fi
 nixos-install --no-root-passwd "${NIXOS_INSTALL_OPTS[@]}" --flake "path:$FLAKE_DIR#default"
 success "System installed (bootloader in place)"
 
+# The user must own their flake — libgit2 refuses repositories owned by
+# someone else, which breaks `home-manager switch` (and theme switching)
+# outright. Resolve real uid/gid from the target after nixos-install
+# created the account (do not hard-code 1000:100 — first free uid or
+# primary group can differ).
+USER_UID=$(nixos-enter --root /mnt -- id -u "$USERNAME") \
+    || fail "Could not resolve uid for install user '$USERNAME' on target"
+USER_GID=$(nixos-enter --root /mnt -- id -g "$USERNAME") \
+    || fail "Could not resolve gid for install user '$USERNAME' on target"
+chown -R "$USER_UID:$USER_GID" "$FLAKE_DIR"
+
 # Pre-activate the Home Manager generation so the FIRST boot lands in the
 # fully themed desktop, not bare Hyprland. Best-effort: a failure here
 # only costs the user one `home-manager switch` after logging in.
@@ -629,8 +636,8 @@ else
     tail -n 5 /mnt/var/log/nomarchy-hm-preactivate.log 2>/dev/null || true
     # The live session (and this warning) ends with this install — drop a
     # durable hint on the TARGET so the fix still surfaces on first login.
-    # Numeric ids: the account doesn't exist in the live environment yet
-    # (same reasoning as the $FLAKE_DIR chown above).
+    # Numeric ids from the target account (USER_UID/USER_GID above) — the
+    # name does not exist in the live ISO's passwd.
     hint_file="/mnt/home/$USERNAME/NOMARCHY-DESKTOP-NOT-THEMED.txt"
     cat > "$hint_file" <<HINT
 Desktop pre-activation failed during install — see
@@ -640,7 +647,7 @@ Desktop pre-activation failed during install — see
 
 (delete this file once done)
 HINT
-    chown 1000:100 "$hint_file"
+    chown "$USER_UID:$USER_GID" "$hint_file"
 fi
 rm -f /mnt/root/nomarchy-hm-activate.sh