diff --git a/test/run_boot_test.ps1 b/test/run_boot_test.ps1
index 41e5b925..a7458671 100644
--- a/test/run_boot_test.ps1
+++ b/test/run_boot_test.ps1
@@ -61,7 +61,7 @@ $cfgFile = Join-Path $repoRoot ".opencode\serial_config.json"
 # -Port default: the single source of truth is .opencode/serial_config.json
 if (-not $Port) {
     if (Test-Path -LiteralPath $cfgFile) {
-        $Port = (Get-Content -LiteralPath $cfgFile -Raw | ConvertFrom-Json).portName
+        $Port = (Get-Content -LiteralPath $cfgFile -Raw -Encoding UTF8 | ConvertFrom-Json).portName
     }
 }
 if (-not $Port) {