diff --git a/scripts/proxmox-install.sh b/scripts/proxmox-install.sh
index 20840dd..d963f18 100644
--- a/scripts/proxmox-install.sh
+++ b/scripts/proxmox-install.sh
@@ -11,8 +11,8 @@
 set -euo pipefail
 
 # ── Defaults ───────────────────────────────────────────────────────────────
-REPO="https://github.com/openhop-dev/openhop_repeater.git"
-BRANCH="dev"
+REPO="${OPENHOP_REPO:-https://github.com/openhop-dev/openhop_repeater.git}"
+BRANCH="${OPENHOP_BRANCH:-dev}"
 CT_TEMPLATE="debian-13-standard"
 CT_RAM=1024
 CT_SWAP=512
diff --git a/tests/test_proxmox_installer.py b/tests/test_proxmox_installer.py
index a5d29a0..1146018 100644
--- a/tests/test_proxmox_installer.py
+++ b/tests/test_proxmox_installer.py
@@ -15,6 +15,13 @@ def test_proxmox_installer_uses_debian_13() -> None:
     assert "Debian 12" not in script
 
 
+def test_installer_allows_explicit_repository_and_branch_for_fork_testing() -> None:
+    script = INSTALLER.read_text()
+
+    assert 'REPO="${OPENHOP_REPO:-https://github.com/openhop-dev/openhop_repeater.git}"' in script
+    assert 'BRANCH="${OPENHOP_BRANCH:-dev}"' in script
+
+
 def test_ch341_host_rule_is_opt_in() -> None:
     script = INSTALLER.read_text()