diff --git a/nimbus/vm/computation.nim b/nimbus/vm/computation.nim
index 9e21055d5..04c27c081 100644
--- a/nimbus/vm/computation.nim
+++ b/nimbus/vm/computation.nim
@@ -131,7 +131,7 @@ proc getFork*(computation: BaseComputation): Fork =
     else:
       computation.vmState.blockNumber.toFork
 
-proc writeContract*(computation: BaseComputation, fork: Fork): bool =
+proc writeContract*(computation: BaseComputation, fork: Fork): bool {.gcsafe.} =
   result = true
 
   let contractCode = computation.output
@@ -172,11 +172,11 @@ template continuation*(comp: BaseComputation, body: untyped) =
   # this is a helper template to implement continuation
   # passing and convert all recursion into tail call
   var tmpNext = comp.nextProc
-  comp.nextProc = proc() =
+  comp.nextProc = proc() {.gcsafe.} =
     body
     tmpNext()
 
-proc postExecuteVM(computation: BaseComputation, opCode: static[Op]) =
+proc postExecuteVM(computation: BaseComputation, opCode: static[Op]) {.gcsafe.} =
   when opCode == Create:
     if computation.isSuccess:
       let fork = computation.getFork
diff --git a/nimbus/vm/interpreter/gas_costs.nim b/nimbus/vm/interpreter/gas_costs.nim
index 63a6a4d6d..4ba2fd8f1 100644
--- a/nimbus/vm/interpreter/gas_costs.nim
+++ b/nimbus/vm/interpreter/gas_costs.nim
@@ -96,11 +96,11 @@ type
     of GckFixed:
       cost*: GasInt
     of GckDynamic:
-      d_handler*: proc(value: Uint256): GasInt {.nimcall.}
+      d_handler*: proc(value: Uint256): GasInt {.nimcall, gcsafe.}
     of GckMemExpansion:
-      m_handler*: proc(currentMemSize, memOffset, memLength: Natural): GasInt {.nimcall.}
+      m_handler*: proc(currentMemSize, memOffset, memLength: Natural): GasInt {.nimcall, gcsafe.}
     of GckComplex:
-      c_handler*: proc(value: Uint256, gasParams: GasParams): GasResult {.nimcall.}
+      c_handler*: proc(value: Uint256, gasParams: GasParams): GasResult {.nimcall, gcsafe.}
       # We use gasCost/gasRefund for:
       #   - Properly log and order cost and refund (for Sstore especially)
       #   - Allow to use unsigned integer in the future
@@ -362,13 +362,13 @@ template gasCosts(fork: Fork, prefix, ResultGasCostsName: untyped) =
     func fixed(gasFeeKind: static[GasFeeKind]): GasCost =
       GasCost(kind: GckFixed, cost: static(FeeSchedule[gasFeeKind]))
 
-    func dynamic(handler: proc(value: Uint256): GasInt {.nimcall.}): GasCost =
+    func dynamic(handler: proc(value: Uint256): GasInt {.nimcall, gcsafe.}): GasCost =
       GasCost(kind: GckDynamic, d_handler: handler)
 
-    func memExpansion(handler: proc(currentMemSize, memOffset, memLength: Natural): GasInt {.nimcall.}): GasCost =
+    func memExpansion(handler: proc(currentMemSize, memOffset, memLength: Natural): GasInt {.nimcall, gcsafe.}): GasCost =
       GasCost(kind: GckMemExpansion, m_handler: handler)
 
-    func complex(handler: proc(value: Uint256, gasParams: GasParams): GasResult {.nimcall.}): GasCost =
+    func complex(handler: proc(value: Uint256, gasParams: GasParams): GasResult {.nimcall, gcsafe.}): GasCost =
       GasCost(kind: GckComplex, c_handler: handler)
 
     # Returned value
diff --git a/nimbus/vm/interpreter/utils/macros_procs_opcodes.nim b/nimbus/vm/interpreter/utils/macros_procs_opcodes.nim
index 612c5becd..476fa8686 100644
--- a/nimbus/vm/interpreter/utils/macros_procs_opcodes.nim
+++ b/nimbus/vm/interpreter/utils/macros_procs_opcodes.nim
@@ -64,7 +64,7 @@ macro op*(procname: untyped, inline: static[bool], stackParams_body: varargs[unt
         `body`
   else:
     result = quote do:
-      proc `procname`*(`computation`: BaseComputation) =
+      proc `procname`*(`computation`: BaseComputation) {.gcsafe.} =
         `popStackStmt`
         `body`
 
diff --git a/nimbus/vm/interpreter_dispatch.nim b/nimbus/vm/interpreter_dispatch.nim
index 008be60b2..b1e9f41fd 100644
--- a/nimbus/vm/interpreter_dispatch.nim
+++ b/nimbus/vm/interpreter_dispatch.nim
@@ -272,10 +272,10 @@ proc homesteadVM(computation: BaseComputation) =
 proc tangerineVM(computation: BaseComputation) =
   genTangerineDispatch(computation)
 
-proc spuriousVM(computation: BaseComputation) =
+proc spuriousVM(computation: BaseComputation) {.gcsafe.} =
   genSpuriousDispatch(computation)
 
-proc selectVM(computation: BaseComputation, fork: Fork) =
+proc selectVM(computation: BaseComputation, fork: Fork) {.gcsafe.} =
   # TODO: Optimise getting fork and updating opCodeExec only when necessary
   case fork
   of FkFrontier..FkThawing:
diff --git a/nimbus/vm_types.nim b/nimbus/vm_types.nim
index 354925e4c..10899b100 100644
--- a/nimbus/vm_types.nim
+++ b/nimbus/vm_types.nim
@@ -70,7 +70,7 @@ type
     instr*:                 Op
     opIndex*:               int
     # continuation helpers
-    nextProc*:              proc()
+    nextProc*:              proc() {.gcsafe.}
     memOutLen*:             int
     memOutPos*:             int
     child*:                 BaseComputation
diff --git a/vendor/nim-json-rpc b/vendor/nim-json-rpc
index 2d3db8813..92a7b78f4 160000
--- a/vendor/nim-json-rpc
+++ b/vendor/nim-json-rpc
@@ -1 +1 @@
-Subproject commit 2d3db88137ccf62a3d9fcbcecefd32f6a86bec91
+Subproject commit 92a7b78f4a2b13bd56260694c0035f7c71f10cb5