diff --git a/.github/scripts/defaults.sh b/.github/scripts/defaults.sh
index 6ca434fb..57fdfaa8 100755
--- a/.github/scripts/defaults.sh
+++ b/.github/scripts/defaults.sh
@@ -23,6 +23,11 @@ LOCAL_CHIPYARD_DIR=$GITHUB_WORKSPACE
 LOCAL_SIM_DIR=$LOCAL_CHIPYARD_DIR/sims/verilator
 LOCAL_FIRESIM_DIR=$LOCAL_CHIPYARD_DIR/sims/firesim/sim
 
+# CI uses temp directories with very long names
+# explicitly force socket creation to use /tmp to avoid name length errors
+# https://github.com/sbt/sbt/pull/6887
+JAVA_TMP_DIR=$(mktemp -d -t ci-cy-XXXXXXXX)
+
 # key value store to get the build groups
 declare -A grouping
 grouping["group-cores"]="chipyard-cva6 chipyard-ibex chipyard-rocket chipyard-hetero chipyard-boom chipyard-sodor chipyard-digitaltop chipyard-multiclock-rocket chipyard-nomem-scratchpad chipyard-spike chipyard-clone"
diff --git a/.github/scripts/remote-do-rtl-build.sh b/.github/scripts/remote-do-rtl-build.sh
index 0e887e9a..b5755d01 100755
--- a/.github/scripts/remote-do-rtl-build.sh
+++ b/.github/scripts/remote-do-rtl-build.sh
@@ -53,5 +53,5 @@ read -a keys <<< ${grouping[$1]}
 for key in "${keys[@]}"
 do
     export COURSIER_CACHE=$REMOTE_WORK_DIR/.coursier-cache
-    make -j$REMOTE_MAKE_NPROC -C $REMOTE_MAKE_DIR FIRRTL_LOGLEVEL=info JAVA_OPTS="$REMOTE_JAVA_OPTS" SBT_OPTS="$REMOTE_SBT_OPTS" ${mapping[$key]}
+    make -j$REMOTE_MAKE_NPROC -C $REMOTE_MAKE_DIR FIRRTL_LOGLEVEL=info JAVA_TMP_DIR=$JAVA_TMP_DIR SBT_OPTS="$REMOTE_SBT_OPTS" ${mapping[$key]}
 done
diff --git a/.github/scripts/remote-run-firesim-scala-tests.sh b/.github/scripts/remote-run-firesim-scala-tests.sh
index 6d475921..960d1706 100755
--- a/.github/scripts/remote-run-firesim-scala-tests.sh
+++ b/.github/scripts/remote-run-firesim-scala-tests.sh
@@ -16,4 +16,5 @@ cd $REMOTE_CHIPYARD_DIR
 # Run Firesim Scala Tests
 export FIRESIM_ENV_SOURCED=1;
 export COURSIER_CACHE=$REMOTE_WORK_DIR/.coursier-cache
-make -C $REMOTE_FIRESIM_DIR JAVA_OPTS="$REMOTE_JAVA_OPTS" SBT_OPTS="$REMOTE_SBT_OPTS" TARGET_SBT_PROJECT="{file:$REMOTE_CHIPYARD_DIR}firechip" testOnly ${mapping[$1]}
+JAVA_TOOL_OPTIONS="$REMOTE_JAVA_OPTS -Djava.io.tmpdir=$(mktemp -d -t cy-fsim-XXXXXXXX)"
+make -C $REMOTE_FIRESIM_DIR JAVA_TOOL_OPTIONS="$JAVA_TOOL_OPTIONS" SBT_OPTS="$REMOTE_SBT_OPTS" TARGET_SBT_PROJECT="{file:$REMOTE_CHIPYARD_DIR}firechip" testOnly ${mapping[$1]}
diff --git a/.github/workflows/chipyard-full-flow.yml b/.github/workflows/chipyard-full-flow.yml
index cc2168e8..22382571 100644
--- a/.github/workflows/chipyard-full-flow.yml
+++ b/.github/workflows/chipyard-full-flow.yml
@@ -13,6 +13,7 @@ defaults:
 
 env:
   REMOTE_WORK_DIR: ${{ secrets.BUILDDIR }}/cy-ci-shared/cy-${{ github.sha }}
+  JAVA_TMP_DIR: /tmp/cy-${{ github.sha }}-full
 
 jobs:
   cancel-prior-workflows:
diff --git a/fpga/Makefile b/fpga/Makefile
index 037b2fb9..79bdb338 100644
--- a/fpga/Makefile
+++ b/fpga/Makefile
@@ -90,11 +90,14 @@ fpga_common_script_dir := $(fpga_dir)/common/tcl
 #########################################################################################
 # setup misc. sim files
 #########################################################################################
+SIM_FILE_REQS += \
+	$(ROCKETCHIP_RSRCS_DIR)/vsrc/EICG_wrapper.v
+
 # copy files but ignore *.h files in *.f (match vcs)
-$(sim_files): $(SIM_FILE_REQS) | $(GEN_COLLATERAL_DIR)
-	cp -f $^ $(GEN_COLLATERAL_DIR)
+$(sim_files): $(SIM_FILE_REQS) $(ALL_MODS_FILELIST) | $(GEN_COLLATERAL_DIR)
+	cp -f $(SIM_FILE_REQS) $(GEN_COLLATERAL_DIR)
 	$(foreach file,\
-		$^,\
+		$(SIM_FILE_REQS),\
 		$(if $(filter %.h,$(file)),\
 			,\
 			echo "$(addprefix $(GEN_COLLATERAL_DIR)/, $(notdir $(file)))" >> $@;))
diff --git a/sims/vcs/Makefile b/sims/vcs/Makefile
index b26df843..b6f11a80 100644
--- a/sims/vcs/Makefile
+++ b/sims/vcs/Makefile
@@ -38,10 +38,10 @@ SIM_FILE_REQS += \
 	$(ROCKETCHIP_RSRCS_DIR)/vsrc/TestDriver.v
 
 # copy files but ignore *.h files in *.f since vcs has +incdir+$(build_dir)
-$(sim_files): $(SIM_FILE_REQS) | $(GEN_COLLATERAL_DIR)
-	cp -f $^ $(GEN_COLLATERAL_DIR)
+$(sim_files): $(SIM_FILE_REQS) $(ALL_MODS_FILELIST) | $(GEN_COLLATERAL_DIR)
+	cp -f $(SIM_FILE_REQS) $(GEN_COLLATERAL_DIR)
 	$(foreach file,\
-		$^,\
+		$(SIM_FILE_REQS),\
 		$(if $(filter %.h,$(file)),\
 			,\
 			echo "$(addprefix $(GEN_COLLATERAL_DIR)/, $(notdir $(file)))" >> $@;))
diff --git a/sims/verilator/Makefile b/sims/verilator/Makefile
index fd171b4c..d48da28e 100644
--- a/sims/verilator/Makefile
+++ b/sims/verilator/Makefile
@@ -66,10 +66,10 @@ SIM_FILE_REQS += \
 	$(ROCKETCHIP_RSRCS_DIR)/csrc/remote_bitbang.cc
 
 # copy files and add -FI for *.h files in *.f
-$(sim_files): $(SIM_FILE_REQS) | $(GEN_COLLATERAL_DIR)
-	cp -f $^ $(GEN_COLLATERAL_DIR)
+$(sim_files): $(SIM_FILE_REQS) $(ALL_MODS_FILELIST) | $(GEN_COLLATERAL_DIR)
+	cp -f $(SIM_FILE_REQS) $(GEN_COLLATERAL_DIR)
 	$(foreach file,\
-		$^,\
+		$(SIM_FILE_REQS),\
 		$(if $(filter %.h,$(file)),\
 			echo "-FI $(addprefix $(GEN_COLLATERAL_DIR)/, $(notdir $(file)))" >> $@;,\
 			echo "$(addprefix $(GEN_COLLATERAL_DIR)/, $(notdir $(file)))" >> $@;))
diff --git a/variables.mk b/variables.mk
index f10cbfa9..1312cbe3 100644
--- a/variables.mk
+++ b/variables.mk
@@ -202,7 +202,8 @@ sim_common_files       ?= $(build_dir)/sim_files.common.f
 # java arguments used in sbt
 #########################################################################################
 JAVA_HEAP_SIZE ?= 8G
-export JAVA_TOOL_OPTIONS ?= -Xmx$(JAVA_HEAP_SIZE) -Xss8M -Djava.io.tmpdir=$(base_dir)/.java_tmp
+JAVA_TMP_DIR ?= $(base_dir)/.java_tmp
+export JAVA_TOOL_OPTIONS ?= -Xmx$(JAVA_HEAP_SIZE) -Xss8M -Djava.io.tmpdir=$(JAVA_TMP_DIR)
 
 #########################################################################################
 # default sbt launch command
diff --git a/vlsi/Makefile b/vlsi/Makefile
index a1f850a1..ab8438d5 100644
--- a/vlsi/Makefile
+++ b/vlsi/Makefile
@@ -134,10 +134,10 @@ SIM_FILE_REQS += \
 	$(ROCKETCHIP_RSRCS_DIR)/vsrc/TestDriver.v
 
 # copy files but ignore *.h files in *.f since vcs has +incdir+$(build_dir)
-$(sim_files): $(SIM_FILE_REQS) | $(build_dir)
-	cp -f $^ $(build_dir)
+$(sim_files): $(SIM_FILE_REQS) $(ALL_MODS_FILELIST) | $(build_dir)
+	cp -f $(SIM_FILE_REQS) $(build_dir)
 	$(foreach file,\
-		$^,\
+		$(SIM_FILE_REQS),\
 		$(if $(filter %.h,$(file)),\
 			,\
 			echo "$(addprefix $(build_dir)/, $(notdir $(file)))" >> $@;))