diff --git a/codex/codex_patcher.py b/codex/codex_patcher.py
index 57a65bb..4bcc8f4 100755
--- a/codex/codex_patcher.py
+++ b/codex/codex_patcher.py
@@ -458,9 +458,20 @@ def apply_all_patches(config, home_dir=None):
     print(f"  Proxy:   {config['base_url']}")
     print()
 
+    # Clean up stale model_catalog.json from previous broken installs
+    stale_catalog = os.path.join(codex_dir, "model_catalog.json")
+    if os.path.isfile(stale_catalog):
+        os.remove(stale_catalog)
+        print(f"  {YELLOW}Removed stale model_catalog.json{RESET}")
+
     # Read existing config
     existing = read_toml(config_path)
 
+    # Remove model_catalog_json if present (wrong format crashes Codex)
+    if "model_catalog_json" in existing:
+        del existing["model_catalog_json"]
+        print(f"  {YELLOW}Removed model_catalog_json from config (unsupported format){RESET}")
+
     # Backup before any changes
     backup_file(config_path)
 
diff --git a/codex/ucodex_install.ps1 b/codex/ucodex_install.ps1
index 066e0ad..03445f1 100644
--- a/codex/ucodex_install.ps1
+++ b/codex/ucodex_install.ps1
@@ -153,14 +153,34 @@ if ($currentVersion -eq $latestVersion) {
 $codexConfigDir = "$env:USERPROFILE\.codex"
 $codexConfigFile = "$codexConfigDir\config.toml"
 if (Test-Path $codexConfigFile) {
-    # Check if existing config is broken (Codex writes bad TOML with dotted model keys)
     $existingContent = Get-Content $codexConfigFile -Raw -ErrorAction SilentlyContinue
+    $needsCleanup = $false
+
+    # Check 1: broken TOML with dotted model keys (gpt-5.4 parsed as gpt-5 -> 4)
     if ($existingContent -match "gpt-5\s*=" -and $existingContent -match "\{.*:") {
+        Write-Host "  Detected broken TOML (dotted key bug)" -ForegroundColor Yellow
+        $needsCleanup = $true
+    }
+
+    # Check 2: model_catalog_json with wrong format (crashes Codex on startup)
+    if ($existingContent -match "model_catalog_json") {
+        Write-Host "  Detected model_catalog_json (unsupported, removing)" -ForegroundColor Yellow
+        $needsCleanup = $true
+    }
+
+    if ($needsCleanup) {
         Write-Host "  Removing broken config.toml..." -ForegroundColor Yellow
         Remove-Item $codexConfigFile -Force -ErrorAction SilentlyContinue
     }
 }
 
+# Clean up stale model_catalog.json if it exists
+$staleCatalog = "$codexConfigDir\model_catalog.json"
+if (Test-Path $staleCatalog) {
+    Remove-Item $staleCatalog -Force -ErrorAction SilentlyContinue
+    Write-Host "  Removed stale model_catalog.json" -ForegroundColor Yellow
+}
+
 # ---- Apply patches ----
 
 if ($pyCmd) {
diff --git a/codex/ucodex_update.ps1 b/codex/ucodex_update.ps1
index cde2e07..cec93ce 100644
--- a/codex/ucodex_update.ps1
+++ b/codex/ucodex_update.ps1
@@ -93,6 +93,39 @@ if ($oldVer -eq $latestVer) {
     Write-Host "  Updated: $oldVer -> $newVer" -ForegroundColor Green
 }
 
+# ---- Clean up broken config from previous runs ----
+
+$codexConfigDir = "$env:USERPROFILE\.codex"
+$codexConfigFile = "$codexConfigDir\config.toml"
+if (Test-Path $codexConfigFile) {
+    $existingContent = Get-Content $codexConfigFile -Raw -ErrorAction SilentlyContinue
+    $needsCleanup = $false
+
+    # Check 1: broken TOML with dotted model keys
+    if ($existingContent -match "gpt-5\s*=" -and $existingContent -match "\{.*:") {
+        Write-Host "  Detected broken TOML (dotted key bug)" -ForegroundColor Yellow
+        $needsCleanup = $true
+    }
+
+    # Check 2: model_catalog_json with wrong format (crashes Codex)
+    if ($existingContent -match "model_catalog_json") {
+        Write-Host "  Detected model_catalog_json (unsupported, removing)" -ForegroundColor Yellow
+        $needsCleanup = $true
+    }
+
+    if ($needsCleanup) {
+        Write-Host "  Removing broken config.toml..." -ForegroundColor Yellow
+        Remove-Item $codexConfigFile -Force -ErrorAction SilentlyContinue
+    }
+}
+
+# Clean up stale model_catalog.json
+$staleCatalog = "$codexConfigDir\model_catalog.json"
+if (Test-Path $staleCatalog) {
+    Remove-Item $staleCatalog -Force -ErrorAction SilentlyContinue
+    Write-Host "  Removed stale model_catalog.json" -ForegroundColor Yellow
+}
+
 # ---- Download and apply patches ----
 
 $pyCmd = $null