diff --git a/.travis.yml b/.travis.yml
index c0c70cf..116813f 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,20 +1,44 @@
-sudo: false
 language: c
-os:
-  - linux
-  - osx
-dist: xenial
+cache:
+  ccache: true
+  directories:
+    - NimV1
+jobs:
+  include:
+    - os: linux
+      arch: amd64
+      env:
+        - NPROC=2
+        - NIM_DIR=NimDev
+        - NIM_BRANCH=devel
+      dist: xenial
+    - os: linux
+      arch: amd64
+      env:
+        - NPROC=2
+        - NIM_DIR=NimV1
+        - NIM_BRANCH=v1.0.8
+      dist: xenial
+    - os: osx
+      env:
+        - NPROC=2
+        - NIM_DIR=NimDev
+        - NIM_BRANCH=devel
+      before_install:
+        - HOMEBREW_NO_AUTO_UPDATE=1 HOMEBREW_NO_INSTALL_CLEANUP=1 brew install ccache
+    - os: osx
+      env:
+        - NPROC=2
+        - NIM_DIR=NimV1
+        - NIM_BRANCH=v1.0.8
+      before_install:
+        - HOMEBREW_NO_AUTO_UPDATE=1 HOMEBREW_NO_INSTALL_CLEANUP=1 brew install ccache
+
 before_script:
-  - git clone https://github.com/nim-lang/Nim.git
-  - cd Nim
-  - git clone --depth 1 https://github.com/nim-lang/csources
-  - cd csources && sh build.sh
-  - cd ..
-  - bin/nim c koch
-  - ./koch boot -d:release
-  - ./koch nimble
-  - export PATH=$(pwd)/bin:$PATH
-  - cd ..
+  - ./tests/bootstrap.sh
+  - export PATH="$(pwd)/$NIM_DIR/bin:$PATH"
 script:
+  - echo $PATH
+  - nim --version
   - nimble install -y --verbose
   - nimble test
diff --git a/appveyor.yml b/appveyor.yml
index e0c0ce2..5ffb91f 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -3,8 +3,8 @@ version: '{build}'
 cache:
 - x86_64-8.1.0-release-win32-seh-rt_v6-rev0.7z
 - i686-8.1.0-release-win32-dwarf-rt_v6-rev0.7z
-- sqlite-dll-win64-x64-3310100.zip
-- sqlite-dll-win32-x86-3290000.zip
+- NimV1x64
+- NimV1x32
 
 matrix:
   fast_finish: true # set this flag to immediately finish build once one of the jobs fails.
@@ -14,35 +14,39 @@ environment:
     - MINGW_DIR: mingw64
       MINGW_URL: https://sourceforge.net/projects/mingw-w64/files/Toolchains%20targetting%20Win64/Personal%20Builds/mingw-builds/8.1.0/threads-win32/seh/x86_64-8.1.0-release-win32-seh-rt_v6-rev0.7z/download
       MINGW_ARCHIVE: x86_64-8.1.0-release-win32-seh-rt_v6-rev0.7z
-      SQLITE_URL: https://www.sqlite.org/2020/sqlite-dll-win64-x64-3310100.zip
-      SQLITE_ARCHIVE: sqlite-dll-win64-x64-3310100.zip
-      SQLITE_NAME: sqlite3_64.dll
       platform: x64
+      NIM_DIR: NimDev
+      NIM_BRANCH: devel
+
+    - MINGW_DIR: mingw64
+      MINGW_URL: https://sourceforge.net/projects/mingw-w64/files/Toolchains%20targetting%20Win64/Personal%20Builds/mingw-builds/8.1.0/threads-win32/seh/x86_64-8.1.0-release-win32-seh-rt_v6-rev0.7z/download
+      MINGW_ARCHIVE: x86_64-8.1.0-release-win32-seh-rt_v6-rev0.7z
+      platform: x64
+      NIM_DIR: NimV1x64
+      NIM_BRANCH: v1.0.8
+
     - MINGW_DIR: mingw32
       MINGW_URL: https://sourceforge.net/projects/mingw-w64/files/Toolchains%20targetting%20Win32/Personal%20Builds/mingw-builds/8.1.0/threads-win32/dwarf/i686-8.1.0-release-win32-dwarf-rt_v6-rev0.7z/download
       MINGW_ARCHIVE: i686-8.1.0-release-win32-dwarf-rt_v6-rev0.7z
-      SQLITE_URL: https://www.sqlite.org/2020/sqlite-dll-win32-x86-3310100.zip
-      SQLITE_ARCHIVE: sqlite-dll-win32-x86-3310100.zip
-      SQLITE_NAME: sqlite3_32.dll
       platform: x86
+      NIM_DIR: NimDev
+      NIM_BRANCH: devel
+
+    - MINGW_DIR: mingw32
+      MINGW_URL: https://sourceforge.net/projects/mingw-w64/files/Toolchains%20targetting%20Win32/Personal%20Builds/mingw-builds/8.1.0/threads-win32/dwarf/i686-8.1.0-release-win32-dwarf-rt_v6-rev0.7z/download
+      MINGW_ARCHIVE: i686-8.1.0-release-win32-dwarf-rt_v6-rev0.7z
+      platform: x86
+      NIM_DIR: NimV1x32
+      NIM_BRANCH: v1.0.8
 
 install:
   - IF not exist "%MINGW_ARCHIVE%" appveyor DownloadFile "%MINGW_URL%" -FileName "%MINGW_ARCHIVE%"
-  - IF not exist "%SQLITE_ARCHIVE%" appveyor DownloadFile "%SQLITE_URL%" -FileName "%SQLITE_ARCHIVE%"
   - 7z x -y "%MINGW_ARCHIVE%" > nul
-  - SET PATH=%CD%\%MINGW_DIR%\bin;%CD%\Nim\bin;%PATH%
-  - git clone https://github.com/nim-lang/Nim.git %CD%\Nim
-  - 7z x -y "%SQLITE_ARCHIVE%" -o"%CD%\Nim\bin" > nul
-  - RENAME "%CD%\Nim\bin\sqlite3.dll" "%SQLITE_NAME%"
-  - cd %CD%\Nim
-  - git clone --depth 1 https://github.com/nim-lang/csources
-  - cd csources
-  - IF "%PLATFORM%" == "x64" ( build64.bat ) else ( build.bat )
-  - cd ..
-  - bin\nim c koch
-  - koch boot -d:release
-  - koch nimble
+  - SET PATH=%CD%\%MINGW_DIR%\bin;%CD%\%NIM_DIR%\bin;%PATH%
+  - tests/bootstrap.bat
 build_script:
+  - echo %PATH%
+  - nim --version
   - cd C:\projects\nimcrypto
   - nimble install -y --verbose
 test_script:
diff --git a/nimcrypto.nimble b/nimcrypto.nimble
index 65088ef..49966c7 100644
--- a/nimcrypto.nimble
+++ b/nimcrypto.nimble
@@ -1,6 +1,6 @@
 # Package
 
-version       = "0.5.3"
+version       = "0.5.4"
 author        = "Eugene Kabanov"
 description   = "Nim cryptographic library"
 license       = "MIT"
diff --git a/nimcrypto/scrypt.nim b/nimcrypto/scrypt.nim
index c1146b8..472f0ba 100644
--- a/nimcrypto/scrypt.nim
+++ b/nimcrypto/scrypt.nim
@@ -188,7 +188,7 @@ func validateParam(N, r, p: int): bool =
     maxIntd256 = maxInt div 256
 
   let
-    badParam1 = uint64(r)*uint64(p) >= 1 shl 30
+    badParam1 = (uint64(r) * uint64(p)) >= uint64(1 shl 30)
     badParam2 = r > maxIntd128 div p
     badParam3 = r > maxIntd256
     badParam4 = N > maxIntd128 div r
diff --git a/nimcrypto/utils.nim b/nimcrypto/utils.nim
index ca04954..b110a82 100644
--- a/nimcrypto/utils.nim
+++ b/nimcrypto/utils.nim
@@ -87,7 +87,7 @@ proc bytesToHex*(src: openarray[byte], dst: var openarray[char],
       dst[k + 0] = hexDigit(x shr 4, lowercase)
       inc(k)
 
-    return k
+    k
 
 proc hexToBytes*(src: openarray[char], dst: var openarray[byte],
                  flags: set[HexFlags]): int =
diff --git a/tests/bootstrap.bat b/tests/bootstrap.bat
new file mode 100644
index 0000000..d47a986
--- /dev/null
+++ b/tests/bootstrap.bat
@@ -0,0 +1,25 @@
+@echo off
+IF NOT EXIST "%CD%\%NIM_DIR%\bin\nim.exe" (
+  echo Building Nim [%NIM_BRANCH%] in %NIM_DIR%
+  git clone https://github.com/nim-lang/Nim.git "%CD%\%NIM_DIR%"
+  cd "%CD%\%NIM_DIR%"
+  IF NOT "%NIM_BRANCH%" == "devel" (
+    git checkout "tags/%NIM_BRANCH%" -b "%NIM_BRANCH%"
+  ) ELSE (
+    git checkout devel
+  )
+  git clone --depth 1 https://github.com/nim-lang/csources
+  cd csources
+  IF "%PLATFORM%" == "x64" ( build64.bat ) else ( build.bat )
+  cd ..
+  bin\nim c -d:release koch
+  koch boot -d:release
+  koch nimble
+  cd ..
+) ELSE (
+  cd "%CD%\%NIM_DIR%"
+  set GITBRANCH=
+  for /f %%I in ('git.exe rev-parse --abbrev-ref HEAD 2^> NUL') do set GITBRANCH=%%I
+  echo Using Nim [%GITBRANCH%] in %NIM_DIR%
+  cd ..
+)
diff --git a/tests/bootstrap.sh b/tests/bootstrap.sh
new file mode 100755
index 0000000..f53727b
--- /dev/null
+++ b/tests/bootstrap.sh
@@ -0,0 +1,21 @@
+#!/usr/bin/env bash
+if [ ! -e "$NIM_DIR/bin/nim" ]; then
+  echo "Building Nim [$NIM_BRANCH] in $NIM_DIR"
+  git clone https://github.com/nim-lang/Nim.git "$NIM_DIR"
+  cd "$NIM_DIR"
+  if [ "$NIM_BRANCH" = "devel" ]; then
+    git checkout devel
+  else
+    git checkout "tags/$NIM_BRANCH" -b "$NIM_BRANCH"
+  fi
+  git clone --depth 1 https://github.com/nim-lang/csources
+  cd csources && sh build.sh
+  cd ..
+  bin/nim c -d:release koch
+  ./koch boot -d:release
+  ./koch nimble -d:release
+  cd ..
+else
+  GITBRANCH=$(git branch | sed -n -e 's/^\* \(.*\)/\1/p')
+  echo "Using Nim [$GITBRANCH] in $NIM_DIR"
+fi