diff --git a/Configuration/StandardSequences/python/SimL1EmulatorRepack_FullMC_cff.py b/Configuration/StandardSequences/python/SimL1EmulatorRepack_FullMC_cff.py
index a24d0ece093f6..15273b80f2c2f 100644
--- a/Configuration/StandardSequences/python/SimL1EmulatorRepack_FullMC_cff.py
+++ b/Configuration/StandardSequences/python/SimL1EmulatorRepack_FullMC_cff.py
@@ -25,6 +25,10 @@ def _print(ignored):
 unpackCSC = EventFilter.CSCRawToDigi.cscUnpacker_cfi.muonCSCDigis.clone(
     InputObjects = cms.InputTag( 'rawDataCollector', processName=cms.InputTag.skipCurrentProcess()))
 
+import EventFilter.GEMRawToDigi.muonGEMDigis_cfi
+unpackGEM = EventFilter.GEMRawToDigi.muonGEMDigis_cfi.muonGEMDigis.clone(
+    InputLabel = cms.InputTag( 'rawDataCollector', processName=cms.InputTag.skipCurrentProcess()))
+
 import EventFilter.EcalRawToDigi.EcalUnpackerData_cfi
 unpackEcal = EventFilter.EcalRawToDigi.EcalUnpackerData_cfi.ecalEBunpacker.clone(
     InputLabel = cms.InputTag( 'rawDataCollector', processName=cms.InputTag.skipCurrentProcess()))
@@ -84,6 +88,9 @@ def _print(ignored):
 simCaloStage2Layer1Digis.ecalToken = 'unpackEcal:EcalTriggerPrimitives'
 simCaloStage2Layer1Digis.hcalToken = 'simHcalTriggerPrimitiveDigis'
 
+# GEM
+simMuonGEMPadDigis.InputCollection = 'unpackGEM'
+
 # Finally, pack the new L1T output back into RAW
 from EventFilter.L1TRawToDigi.caloStage2Raw_cfi import caloStage2Raw as packCaloStage2
 from EventFilter.L1TRawToDigi.gmtStage2Raw_cfi import gmtStage2Raw as packGmtStage2
@@ -105,6 +112,7 @@ def _print(ignored):
 stage2L1Trigger.toReplaceWith(SimL1EmulatorTask, cms.Task(unpackRPC
                                                           , unpackDT
                                                           , unpackCSC
+                                                          , unpackGEM
                                                           , unpackEcal
                                                           , unpackHcal
                                                           #, simEcalTriggerPrimitiveDigis
diff --git a/HLTrigger/Configuration/python/customizeHLTforCMSSW.py b/HLTrigger/Configuration/python/customizeHLTforCMSSW.py
index 2abc5cce7e82c..a05620f102484 100644
--- a/HLTrigger/Configuration/python/customizeHLTforCMSSW.py
+++ b/HLTrigger/Configuration/python/customizeHLTforCMSSW.py
@@ -3,6 +3,9 @@
 # helper fuctions
 from HLTrigger.Configuration.common import *
 
+# dd4hep
+from Configuration.ProcessModifiers.dd4hep_cff import dd4hep
+
 # add one customisation function per PR
 # - put the PR number into the name of the function
 # - add a short comment
@@ -129,10 +132,21 @@ def customiseFor2018Input(process):
     return process
 
 
+#temporary solution to add GEM geometry for hltGetConfiguration
+def customiseFor34788(process):
+    """Add GEM geometry to output from hltGetConfiguration"""
+    process.load("Geometry.GEMGeometryBuilder.gemGeometryDB_cfi")
+
+    return process
+
 # CMSSW version specific customizations
 def customizeHLTforCMSSW(process, menuType="GRun"):
     
     # add call to action function in proper order: newest last!
     # process = customiseFor12718(process)
 
+    # temporary for GEM
+    if menuType in ["GRun","HIon","PIon","PRef"]:
+        (~dd4hep).makeProcessModifier(customiseFor34788).apply(process)
+
     return process