diff --git a/.travis.yml b/.travis.yml
index 32a40bcaf0aa..ea5d54eadc1c 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -14,8 +14,9 @@ matrix:
     - os: osx
       env: NIM_COMPILE_TO_CPP=true
 
-  allow_failures:
-    - env: NIM_COMPILE_TO_CPP=true
+# To allow failures for a failing configuration, use something like:
+#  allow_failures:
+#    - env: NIM_COMPILE_TO_CPP=true
 #    - os: osx
 
 addons:
diff --git a/koch.nim b/koch.nim
index be8f75986927..f70cf21425a1 100644
--- a/koch.nim
+++ b/koch.nim
@@ -281,19 +281,24 @@ proc boot(args: string) =
   let smartNimcache = (if "release" in args: "nimcache/r_" else: "nimcache/d_") &
                       hostOs & "_" & hostCpu
 
-  copyExe(findStartNim(), 0.thVersion)
-  for i in 0..2+ord(useCpp):
-    # do the first iteration in C mode in order to avoid problem #10315:
-    let defaultCommand = if useCpp and i > 0: "cpp" else: "c"
+  let nimStart = findStartNim()
+  copyExe(nimStart, 0.thVersion)
+  for i in 0..2:
+    let defaultCommand = if useCpp: "cpp" else: "c"
     let bootOptions = if args.len == 0 or args.startsWith("-"): defaultCommand else: ""
-
     echo "iteration: ", i+1
-    let extraOption = if i == 0:
-      "--skipUserCfg --skipParentCfg"
+    var extraOption = ""
+    if i == 0:
+      extraOption.add " --skipUserCfg --skipParentCfg"
         # Note(D20190115T162028:here): the configs are skipped for bootstrap
         # (1st iteration) to prevent newer flags from breaking bootstrap phase.
         # fixes #10030.
-    else: ""
+      let ret = execCmdEx(nimStart & " --version")
+      doAssert ret.exitCode == 0
+      let version = ret.output.splitLines[0]
+      if version.startsWith "Nim Compiler Version 0.19.0":
+        extraOption.add " -d:nimBoostrapCsources0_19_0"
+        # remove this when csources get updated
     exec i.thVersion & " $# $# $# --nimcache:$# compiler" / "nim.nim" %
       [bootOptions, extraOption, args, smartNimcache]
     if sameFileContent(output, i.thVersion):
diff --git a/lib/system.nim b/lib/system.nim
index fb52ee9eb213..b479b920a30d 100644
--- a/lib/system.nim
+++ b/lib/system.nim
@@ -569,7 +569,12 @@ type
       trace: string
     else:
       trace: seq[StackTraceEntry]
-    raiseId: uint # set when exception is raised
+    when defined(nimBoostrapCsources0_19_0):
+      # see #10315, bootstrap with `nim cpp` from csources gave error:
+      # error: no member named 'raise_id' in 'Exception'
+      raise_id: uint # set when exception is raised
+    else:
+      raiseId: uint # set when exception is raised
     up: ref Exception # used for stacking exceptions. Not exported!
 
   Defect* = object of Exception ## \
diff --git a/tests/exception/t9657.nim b/tests/exception/t9657.nim
index 5d5164f4f0d1..c96a0a5976c3 100644
--- a/tests/exception/t9657.nim
+++ b/tests/exception/t9657.nim
@@ -1,6 +1,8 @@
 discard """
   action: run
   exitcode: 1
+  target: "c"
 """
+# todo: remove `target: "c"` workaround once #10343 is properly fixed
 close stdmsg
 writeLine stdmsg, "exception!"