diff --git a/app/Actions.cpp b/app/Actions.cpp
index 1ff5670..0dfe2b1 100644
--- a/app/Actions.cpp
+++ b/app/Actions.cpp
@@ -301,6 +301,7 @@ void MainWindow::OnActionsAddDisks(void)
     DiskImg img;
     CString failed, errMsg;
     CString openFilters, saveFolder;
+    CStringA pathNameA;
     AddFilesDialog addOpts;
 
     LOGI("Add disks!");
@@ -325,7 +326,8 @@ void MainWindow::OnActionsAddDisks(void)
     fPreferences.SetPrefString(kPrAddFileFolder, saveFolder);
 
     /* open the image file and analyze it */
-    dierr = img.OpenImage(dlg.GetPathName(), PathProposal::kLocalFssep, true);
+    pathNameA = dlg.GetPathName();
+    dierr = img.OpenImage(pathNameA, PathProposal::kLocalFssep, true);
     if (dierr != kDIErrNone) {
         errMsg.Format(L"Unable to open disk image: %hs.",
             DiskImgLib::DIStrError(dierr));
diff --git a/app/DiskArchive.cpp b/app/DiskArchive.cpp
index b981cbd..8e426aa 100644
--- a/app/DiskArchive.cpp
+++ b/app/DiskArchive.cpp
@@ -466,13 +466,16 @@ GenericArchive::OpenResult DiskArchive::Open(const WCHAR* filename,
     {
         CWaitCursor waitc;
 
-        dierr = fDiskImg.OpenImage(filename, PathProposal::kLocalFssep, readOnly);
+        CStringA fileNameA(filename);
+        dierr = fDiskImg.OpenImage(fileNameA, PathProposal::kLocalFssep,
+            readOnly);
         if (dierr == kDIErrAccessDenied && !readOnly && !isVolume) {
             // retry file open with read-only set
             // don't do that for volumes -- assume they know what they want
             LOGI("  Retrying open with read-only set");
             fIsReadOnly = readOnly = true;
-            dierr = fDiskImg.OpenImage(filename, PathProposal::kLocalFssep, readOnly);
+            dierr = fDiskImg.OpenImage(fileNameA, PathProposal::kLocalFssep,
+                readOnly);
         }
         if (dierr != kDIErrNone) {
             if (dierr == kDIErrFileArchive)
diff --git a/app/Tools.cpp b/app/Tools.cpp
index bd0e685..420b6aa 100644
--- a/app/Tools.cpp
+++ b/app/Tools.cpp
@@ -167,7 +167,8 @@ void MainWindow::OnToolsDiskEdit(void)
     {
         CWaitCursor waitc;
         /* open the image file and analyze it */
-        dierr = img.OpenImage(loadName, PathProposal::kLocalFssep, true);
+        CStringA loadNameA(loadName);
+        dierr = img.OpenImage(loadNameA, PathProposal::kLocalFssep, true);
     }
 #else
     /* quick test of memory-buffer-based interface */
@@ -343,7 +344,7 @@ void MainWindow::OnToolsDiskConv(void)
     DiskImg srcImg, dstImg;
     DiskConvertDialog convDlg(this);
     CString storageName;
-    CStringA saveNameA, storageNameA;
+    CStringA saveNameA, storageNameA, loadNameA;
 
     /* flush current archive in case that's what we're planning to convert */
     OnFileSave();
@@ -372,7 +373,8 @@ void MainWindow::OnToolsDiskConv(void)
     fPreferences.SetPrefString(kPrOpenArchiveFolder, saveFolder);
 
     /* open the image file and analyze it */
-    dierr = srcImg.OpenImage(loadName, PathProposal::kLocalFssep, true);
+    loadNameA = loadName;
+    dierr = srcImg.OpenImage(loadNameA, PathProposal::kLocalFssep, true);
     if (dierr != kDIErrNone) {
         errMsg.Format(L"Unable to open disk image: %hs.",
             DiskImgLib::DIStrError(dierr));
@@ -1214,7 +1216,8 @@ void MainWindow::BulkConvertImage(const WCHAR* pathName, const WCHAR* targetDir,
                             fPreferences.GetPrefLong(kPrCompressionType));
 
     /* open the image file and analyze it */
-    dierr = srcImg.OpenImage(pathName, PathProposal::kLocalFssep, true);
+    CStringA pathNameA(pathName);
+    dierr = srcImg.OpenImage(pathNameA, PathProposal::kLocalFssep, true);
     if (dierr != kDIErrNone) {
         pErrMsg->Format(L"Unable to open disk image: %hs.",
             DiskImgLib::DIStrError(dierr));
@@ -1625,6 +1628,7 @@ int MainWindow::SSTOpenImage(int seqNum, DiskImg* pDiskImg)
     int result = -1;
     CString openFilters, errMsg;
     CString loadName, saveFolder;
+    CStringA loadNameA;
 
     /*
      * Select the image to convert.
@@ -1650,7 +1654,8 @@ int MainWindow::SSTOpenImage(int seqNum, DiskImg* pDiskImg)
     fPreferences.SetPrefString(kPrOpenArchiveFolder, saveFolder);
 
     /* open the image file and analyze it */
-    dierr = pDiskImg->OpenImage(loadName, PathProposal::kLocalFssep, true);
+    loadNameA = loadName;
+    dierr = pDiskImg->OpenImage(loadNameA, PathProposal::kLocalFssep, true);
     if (dierr != kDIErrNone) {
         errMsg.Format(L"Unable to open disk image: %hs.",
             DiskImgLib::DIStrError(dierr));
@@ -1930,7 +1935,8 @@ void MainWindow::VolumeCopier(bool openFile)
 
         DiskImg::SetAllowWritePhys0(false);
 
-        dierr = srcImg.OpenImage(deviceName, '\0', readOnly);
+        CStringA deviceNameA(deviceName);
+        dierr = srcImg.OpenImage(deviceNameA, '\0', readOnly);
         if (dierr == kDIErrAccessDenied) {
             if (openFile) {
                 errMsg.Format(L"Unable to open '%ls': %hs (try opening the file"
diff --git a/app/VolumeCopyDialog.cpp b/app/VolumeCopyDialog.cpp
index 8f30dad..3acbddd 100644
--- a/app/VolumeCopyDialog.cpp
+++ b/app/VolumeCopyDialog.cpp
@@ -618,7 +618,8 @@ void VolumeCopyDialog::OnCopyFromFile(void)
         CString saveFolder;
 
         /* open the image file and analyze it */
-        dierr = srcImg.OpenImage(loadName, PathProposal::kLocalFssep, true);
+        CStringA loadNameA(loadName);
+        dierr = srcImg.OpenImage(loadNameA, PathProposal::kLocalFssep, true);
         if (dierr != kDIErrNone) {
             errMsg.Format(L"Unable to open disk image: %hs.",
                 DiskImgLib::DIStrError(dierr));
diff --git a/diskimg/DiskImg.cpp b/diskimg/DiskImg.cpp
index b842126..3b8f2c5 100644
--- a/diskimg/DiskImg.cpp
+++ b/diskimg/DiskImg.cpp
@@ -381,12 +381,20 @@ bail:
     return dierr;
 }
 
+DIError DiskImg::OpenImageFromBufferRO(const uint8_t* buffer, long length) {
+    return OpenImageFromBuffer(const_cast<uint8_t*>(buffer), length, true);
+}
+
+DIError DiskImg::OpenImageFromBufferRW(uint8_t* buffer, long length) {
+    return OpenImageFromBuffer(buffer, length, false);
+}
+
 /*
  * Open from a buffer, which could point to unadorned ready-to-go content
  * or to a preloaded image file.
  */
 DIError
-DiskImg::OpenImage(const void* buffer, long length, bool readOnly)
+DiskImg::OpenImageFromBuffer(uint8_t* buffer, long length, bool readOnly)
 {
     if (fpDataGFD != NULL) {
         LOGI(" DI already open!");
@@ -400,8 +408,7 @@ DiskImg::OpenImage(const void* buffer, long length, bool readOnly)
     fReadOnly = readOnly;
     pGFDBuffer = new GFDBuffer;
 
-    dierr = pGFDBuffer->Open(const_cast<void*>(buffer), length, false, false,
-                readOnly);
+    dierr = pGFDBuffer->Open(buffer, length, false, false, readOnly);
     if (dierr != kDIErrNone) {
         delete pGFDBuffer;
         return dierr;
@@ -782,7 +789,8 @@ DiskImg::AnalyzeImageFile(const char* pathName, char fssep)
     } else
         ext = "";
 
-    LOGI(" DI AnalyzeImageFile ext='%s'", ext);
+    LOGI(" DI AnalyzeImageFile '%s' '%c' ext='%s'",
+        pathName, fssep, ext);
 
     /* sanity check: nobody should have configured these yet */
     assert(fOuterFormat == kOuterFormatUnknown);
diff --git a/diskimg/DiskImg.h b/diskimg/DiskImg.h
index 1d161b0..4939118 100644
--- a/diskimg/DiskImg.h
+++ b/diskimg/DiskImg.h
@@ -409,7 +409,9 @@ public:
     // file is on disk; stuff like 2MG headers will be identified and stripped
     DIError OpenImage(const char* filename, char fssep, bool readOnly);
     // file is in memory; provide a pointer to the data start and buffer size
-    DIError OpenImage(const void* buffer, long length, bool readOnly);
+    DIError OpenImageFromBufferRO(const uint8_t* buffer, long length);
+    // file is in memory; provide a pointer to the data start and buffer size
+    DIError OpenImageFromBufferRW(uint8_t* buffer, long length);
     // file is a range of blocks on an open block-oriented disk image
     DIError OpenImage(DiskImg* pParent, long firstBlock, long numBlocks);
     // file is a range of tracks/sectors on an open sector-oriented disk image
@@ -741,6 +743,7 @@ private:
     /* static table of default values */
     static const NibbleDescr kStdNibbleDescrs[];
 
+    DIError OpenImageFromBuffer(uint8_t* buffer, long length, bool readOnly);
     DIError CreateImageCommon(const char* pathName, const char* storageName,
         bool skipFormat);
     DIError ValidateCreateFormat(void) const;
diff --git a/diskimg/GenericFD.cpp b/diskimg/GenericFD.cpp
index 88ed5d0..249740d 100644
--- a/diskimg/GenericFD.cpp
+++ b/diskimg/GenericFD.cpp
@@ -427,7 +427,7 @@ GFDBuffer::Open(void* buffer, di_off_t length, bool doDelete, bool doExpand,
 
     /* if buffer is NULL, allocate it ourselves */
     if (buffer == NULL) {
-        fBuffer = (void*) new char[(int) length];
+        fBuffer = (void*) new uint8_t[(int) length];
         if (fBuffer == NULL)
             return kDIErrMalloc;
     } else