diff --git a/api/logic/java/JavaUtils.cpp b/api/logic/java/JavaUtils.cpp
index ff6a9ac5..4b231e6a 100644
--- a/api/logic/java/JavaUtils.cpp
+++ b/api/logic/java/JavaUtils.cpp
@@ -273,13 +273,13 @@ QList<QString> JavaUtils::FindJavaPaths()
     QList<JavaInstallPtr> ZULU64s = this->FindJavaFromRegistryKey(
         KEY_WOW64_64KEY, "SOFTWARE\\Azul Systems\\Zulu", "InstallationPath");
     QList<JavaInstallPtr> ZULU32s = this->FindJavaFromRegistryKey(
-        KEY_WOW64_64KEY, "SOFTWARE\\Azul Systems\\Zulu", "InstallationPath");
+        KEY_WOW64_32KEY, "SOFTWARE\\Azul Systems\\Zulu", "InstallationPath");
     
     // BellSoft Liberica
     QList<JavaInstallPtr> LIBERICA64s = this->FindJavaFromRegistryKey(
         KEY_WOW64_64KEY, "SOFTWARE\\BellSoft\\Liberica", "InstallationPath");
     QList<JavaInstallPtr> LIBERICA32s = this->FindJavaFromRegistryKey(
-        KEY_WOW64_64KEY, "SOFTWARE\\BellSoft\\Liberica", "InstallationPath");
+        KEY_WOW64_32KEY, "SOFTWARE\\BellSoft\\Liberica", "InstallationPath");
 
     // List x64 before x86
     java_candidates.append(JRE64s);
diff --git a/api/logic/modplatform/modpacksch/FTBPackInstallTask.cpp b/api/logic/modplatform/modpacksch/FTBPackInstallTask.cpp
index ddc7fe35..6067c56a 100644
--- a/api/logic/modplatform/modpacksch/FTBPackInstallTask.cpp
+++ b/api/logic/modplatform/modpacksch/FTBPackInstallTask.cpp
@@ -1,10 +1,12 @@
 #include "FTBPackInstallTask.h"
 
 #include "BuildConfig.h"
+#include "Env.h"
 #include "FileSystem.h"
 #include "Json.h"
 #include "minecraft/MinecraftInstance.h"
 #include "minecraft/PackProfile.h"
+#include "net/ChecksumValidator.h"
 #include "settings/INISettingsObject.h"
 
 namespace ModpacksCH {
@@ -93,11 +95,23 @@ void PackInstallTask::downloadPack()
     for(auto file : m_version.files) {
         if(file.serverOnly) continue;
 
+        QFileInfo fileName(file.name);
+        auto cacheName = fileName.completeBaseName() + "-" + file.sha1 + "." + fileName.suffix();
+
+        auto entry = ENV.metacache()->resolveEntry("ModpacksCHPacks", cacheName);
+        entry->setStale(true);
+
         auto relpath = FS::PathCombine("minecraft", file.path, file.name);
         auto path = FS::PathCombine(m_stagingPath, relpath);
 
         qDebug() << "Will download" << file.url << "to" << path;
-        auto dl = Net::Download::makeFile(file.url, path);
+        filesToCopy[entry->getFullPath()] = path;
+
+        auto dl = Net::Download::makeCached(file.url, entry);
+        if (!file.sha1.isEmpty()) {
+            auto rawSha1 = QByteArray::fromHex(file.sha1.toLatin1());
+            dl->addValidator(new Net::ChecksumValidator(QCryptographicHash::Sha1, rawSha1));
+        }
         jobPtr->addNetAction(dl);
     }
 
@@ -121,6 +135,19 @@ void PackInstallTask::downloadPack()
 
 void PackInstallTask::install()
 {
+    setStatus(tr("Copying modpack files"));
+
+    for (auto iter = filesToCopy.begin(); iter != filesToCopy.end(); iter++) {
+        auto &from = iter.key();
+        auto &to = iter.value();
+        FS::copy fileCopyOperation(from, to);
+        if(!fileCopyOperation()) {
+            qWarning() << "Failed to copy" << from << "to" << to;
+            emitFailed(tr("Failed to copy files"));
+            return;
+        }
+    }
+
     setStatus(tr("Installing modpack"));
 
     auto instanceConfigPath = FS::PathCombine(m_stagingPath, "instance.cfg");
diff --git a/api/logic/modplatform/modpacksch/FTBPackInstallTask.h b/api/logic/modplatform/modpacksch/FTBPackInstallTask.h
index 4f7786fd..3b2d60de 100644
--- a/api/logic/modplatform/modpacksch/FTBPackInstallTask.h
+++ b/api/logic/modplatform/modpacksch/FTBPackInstallTask.h
@@ -37,6 +37,8 @@ private:
     QString m_version_name;
     Version m_version;
 
+    QMap<QString, QString> filesToCopy;
+
 };
 
 }