diff --git a/build.gradle.kts b/build.gradle.kts
index a0429d4..865a3c7 100644
--- a/build.gradle.kts
+++ b/build.gradle.kts
@@ -6,7 +6,7 @@ import kotlin.math.max
 
 plugins {
     // Apply the Kotlin JVM plugin to add support for Kotlin on the JVM.
-    kotlin("jvm") version "1.3.61"
+    kotlin("jvm") version "1.3.70"
     `maven-publish`
     application
     id("org.jetbrains.dokka") version "0.10.0"
@@ -32,6 +32,9 @@ allprojects {
 
 
 dependencies {
+    // Align versions of all Kotlin components
+    implementation(platform("org.jetbrains.kotlin:kotlin-bom"))
+
     // Use the Kotlin JDK 8 standard library.
     implementation("org.jetbrains.kotlin:kotlin-stdlib-jdk8")
 
diff --git a/src/main/kotlin/razorvine/ksim65/Utils.kt b/src/main/kotlin/razorvine/ksim65/Utils.kt
index a3133b4..0de8330 100644
--- a/src/main/kotlin/razorvine/ksim65/Utils.kt
+++ b/src/main/kotlin/razorvine/ksim65/Utils.kt
@@ -2,20 +2,16 @@ package razorvine.ksim65
 
 import razorvine.ksim65.components.Address
 
-fun hexW(number: Address, allowSingleByte: Boolean = false): String {
-    val msb = number ushr 8
-    val lsb = number and 0xff
-    return if (msb == 0 && allowSingleByte) hexB(lsb)
-    else hexB(msb)+hexB(lsb)
-}
+fun hexW(number: Int, allowSingleByte: Boolean = false) =
+        if(allowSingleByte && (number and 0xff00 == 0)) {
+            number.toString(16).padStart(2, '0')
+        } else {
+            number.toString(16).padStart(4, '0')
+        }
 
-fun hexB(number: Short): String = hexB(number.toInt())
 
-fun hexB(number: Int): String {
-    val hexdigits = "0123456789abcdef"
-    val loNibble = number and 15
-    val hiNibble = (number and 65535) ushr 4
-    return hexdigits[hiNibble].toString()+hexdigits[loNibble]
-}
+fun hexB(number: Int) = number.toString(16).padStart(2, '0')
+
+fun hexB(number: Short) = hexB(number.toInt())
 
 typealias BreakpointHandler = (cpu: Cpu6502, pc: Address) -> Cpu6502.BreakpointResultAction
diff --git a/src/test/kotlin/TestDisassembler.kt b/src/test/kotlin/TestDisassembler.kt
index 4ef21d9..e95304c 100644
--- a/src/test/kotlin/TestDisassembler.kt
+++ b/src/test/kotlin/TestDisassembler.kt
@@ -33,7 +33,7 @@ class TestDisassembler {
         val cpu = Cpu65C02()
         val disassembler = Disassembler(cpu)
         val memory = Ram(0, 0x0fff)
-        val source = javaClass.classLoader.getResource("disassem_r65c02.bin").readBytes()
+        val source = javaClass.classLoader.getResource("disassem_r65c02.bin")?.readBytes()!!
         memory.load(source, 0x0200)
         val disassem = disassembler.disassemble(memory.data, 0x0200..0x0250, 0)
         assertEquals(0x251, disassem.second)
@@ -80,7 +80,7 @@ ${'$'}0250  00          brk""", result)
         val cpu = Cpu65C02()
         val disassembler = Disassembler(cpu)
         val memory = Ram(0, 0x0fff)
-        val source = javaClass.classLoader.getResource("disassem_wdc65c02.bin").readBytes()
+        val source = javaClass.classLoader.getResource("disassem_wdc65c02.bin")?.readBytes()!!
         memory.load(source, 0x200)
         val disassem = disassembler.disassemble(memory.data, 0x0200..0x0215, 0)
         assertEquals(0x216, disassem.second)