diff --git a/generators/firechip/src/main/scala/TargetConfigs.scala b/generators/firechip/src/main/scala/TargetConfigs.scala
index 7af98c57a7..621a152c97 100644
--- a/generators/firechip/src/main/scala/TargetConfigs.scala
+++ b/generators/firechip/src/main/scala/TargetConfigs.scala
@@ -186,6 +186,22 @@ class FireSimRocketConfig extends Config(
   new chipyard.RocketConfig)
 // DOC include end: firesimconfig
 
+class FireSimRocket1GiBDRAMConfig extends Config(
+  new freechips.rocketchip.subsystem.WithExtMemSize((1 << 30) * 1L) ++
+  new FireSimRocketConfig)
+
+class FireSimRocketMMIOOnly1GiBDRAMConfig extends Config(
+  new freechips.rocketchip.subsystem.WithExtMemSize((1 << 30) * 1L) ++
+  new FireSimRocketMMIOOnlyConfig)
+
+class FireSimRocket4GiBDRAMConfig extends Config(
+  new freechips.rocketchip.subsystem.WithExtMemSize((1 << 30) * 4L) ++
+  new FireSimRocketConfig)
+
+class FireSimRocketMMIOOnly4GiBDRAMConfig extends Config(
+  new freechips.rocketchip.subsystem.WithExtMemSize((1 << 30) * 4L) ++
+  new FireSimRocketMMIOOnlyConfig)
+
 class FireSimQuadRocketConfig extends Config(
   new WithDefaultFireSimBridges ++
   new WithDefaultMemModel ++