diff --git a/src/FruDevice.cpp b/src/FruDevice.cpp
index 42ca311..4d93fc1 100644
--- a/src/FruDevice.cpp
+++ b/src/FruDevice.cpp
@@ -650,12 +650,19 @@
         {
             busnum.erase(0, lastDash + 1);
         }
+
         auto bus = std::stoi(busnum);
         if (busBlacklist.find(bus) != busBlacklist.end())
         {
             continue; // skip previously failed busses
         }
 
+        int rootBus = getRootBus(bus);
+        if (busBlacklist.find(rootBus) != busBlacklist.end())
+        {
+            continue;
+        }
+
         auto file = open(i2cBus.c_str(), O_RDWR);
         if (file < 0)
         {