diff --git a/src/miniz/miniz.c b/src/miniz/miniz.c
index 36be26b28..03456d759 100644
--- a/src/miniz/miniz.c
+++ b/src/miniz/miniz.c
@@ -6683,6 +6683,7 @@ mz_bool mz_zip_writer_add_staged_open(mz_zip_archive* pZip, mz_zip_writer_staged
     mz_zip_internal_state* pState;
 
     memset(pContext, 0, sizeof(mz_zip_writer_staged_context));
+    pContext->pZip = pZip;
     pContext->gen_flags = MZ_ZIP_LDH_BIT_FLAG_HAS_LOCATOR;
     pContext->uncomp_crc32 = MZ_CRC32_INIT;
     pContext->method = MZ_DEFLATED;
@@ -6774,7 +6775,7 @@ mz_bool mz_zip_writer_add_staged_open(mz_zip_archive* pZip, mz_zip_writer_staged
 
     if (pZip->m_file_offset_alignment)
     {
-        MZ_ASSERT((cur_archive_file_ofs & (pZip->m_file_offset_alignment - 1)) == 0);
+        MZ_ASSERT((pContext->cur_archive_file_ofs & (pZip->m_file_offset_alignment - 1)) == 0);
     }
 
     MZ_CLEAR_OBJ(local_dir_header);
@@ -6857,12 +6858,13 @@ mz_bool mz_zip_writer_add_staged_open(mz_zip_archive* pZip, mz_zip_writer_staged
     return MZ_TRUE;
 }
 
-mz_bool mz_zip_writer_add_staged_data(mz_zip_archive *pZip, mz_zip_writer_staged_context *pContext, const char *pRead_buf, size_t read_buf_size)
+mz_bool mz_zip_writer_add_staged_data(mz_zip_writer_staged_context *pContext, const char *pRead_buf, size_t read_buf_size)
 {
     if (pContext->file_ofs + read_buf_size > pContext->max_size)
     {
-        mz_zip_set_error(pZip, MZ_ZIP_FILE_READ_FAILED);
-        pZip->m_pFree(pZip->m_pAlloc_opaque, pContext->pCompressor);
+        mz_zip_set_error(pContext->pZip, MZ_ZIP_FILE_READ_FAILED);
+        pContext->pZip->m_pFree(pContext->pZip->m_pAlloc_opaque, pContext->pCompressor);
+        pContext->pCompressor = NULL;
         return MZ_FALSE;
     }
 
@@ -6876,7 +6878,7 @@ mz_bool mz_zip_writer_add_staged_data(mz_zip_archive *pZip, mz_zip_writer_staged
         pContext->file_ofs += n;
         pContext->uncomp_crc32 = (mz_uint32)mz_crc32(pContext->uncomp_crc32, (const mz_uint8 *)pRead_buf, n);
 
-        if (pZip->m_pNeeds_keepalive != NULL && pZip->m_pNeeds_keepalive(pZip->m_pIO_opaque))
+        if (pContext->pZip->m_pNeeds_keepalive != NULL && pContext->pZip->m_pNeeds_keepalive(pContext->pZip->m_pIO_opaque))
             flush = TDEFL_FULL_FLUSH;
 
         if (n == 0)
@@ -6889,8 +6891,9 @@ mz_bool mz_zip_writer_add_staged_data(mz_zip_archive *pZip, mz_zip_writer_staged
         }
         else if (status != TDEFL_STATUS_OKAY)
         {
-            mz_zip_set_error(pZip, MZ_ZIP_COMPRESSION_FAILED);
-            pZip->m_pFree(pZip->m_pAlloc_opaque, pContext->pCompressor);
+            mz_zip_set_error(pContext->pZip, MZ_ZIP_COMPRESSION_FAILED);
+            pContext->pZip->m_pFree(pContext->pZip->m_pAlloc_opaque, pContext->pCompressor);
+            pContext->pCompressor = NULL;
             return MZ_FALSE;
         }
         pRead_buf     += n;
@@ -6899,12 +6902,15 @@ mz_bool mz_zip_writer_add_staged_data(mz_zip_archive *pZip, mz_zip_writer_staged
     return MZ_TRUE;
 }
 
-mz_bool mz_zip_writer_add_staged_finish(mz_zip_archive *pZip, mz_zip_writer_staged_context *pContext)
+mz_bool mz_zip_writer_add_staged_finish(mz_zip_writer_staged_context *pContext)
 {
-    if (! mz_zip_writer_add_staged_data(pZip, pContext, NULL, 0))
+    if (! mz_zip_writer_add_staged_data(pContext, NULL, 0) ||
+        // Either never opened, or already finished.
+        ! pContext->pCompressor)
         return MZ_FALSE;
 
-    pZip->m_pFree(pZip->m_pAlloc_opaque, pContext->pCompressor);
+    pContext->pZip->m_pFree(pContext->pZip->m_pAlloc_opaque, pContext->pCompressor);
+    pContext->pCompressor = NULL;
 
     pContext->uncomp_size = pContext->file_ofs;
     pContext->comp_size = pContext->add_state.m_comp_size;
@@ -6919,7 +6925,7 @@ mz_bool mz_zip_writer_add_staged_finish(mz_zip_archive *pZip, mz_zip_writer_stag
         if (pContext->pExtra_data == NULL)
         {
             if (pContext->comp_size > MZ_UINT32_MAX)
-                return mz_zip_set_error(pZip, MZ_ZIP_ARCHIVE_TOO_LARGE);
+                return mz_zip_set_error(pContext->pZip, MZ_ZIP_ARCHIVE_TOO_LARGE);
 
             MZ_WRITE_LE32(local_dir_footer + 8, pContext->comp_size);
             MZ_WRITE_LE32(local_dir_footer + 12, pContext->uncomp_size);
@@ -6931,7 +6937,7 @@ mz_bool mz_zip_writer_add_staged_finish(mz_zip_archive *pZip, mz_zip_writer_stag
             local_dir_footer_size = MZ_ZIP_DATA_DESCRIPTER_SIZE64;
         }
 
-        if (pZip->m_pWrite(pZip->m_pIO_opaque, pContext->cur_archive_file_ofs, local_dir_footer, local_dir_footer_size) != local_dir_footer_size)
+        if (pContext->pZip->m_pWrite(pContext->pZip->m_pIO_opaque, pContext->cur_archive_file_ofs, local_dir_footer, local_dir_footer_size) != local_dir_footer_size)
             return MZ_FALSE;
 
         pContext->cur_archive_file_ofs += local_dir_footer_size;
@@ -6943,13 +6949,13 @@ mz_bool mz_zip_writer_add_staged_finish(mz_zip_archive *pZip, mz_zip_writer_stag
                                                            (pContext->uncomp_size >= MZ_UINT32_MAX) ? &pContext->comp_size : NULL, (pContext->local_dir_header_ofs >= MZ_UINT32_MAX) ? &pContext->local_dir_header_ofs : NULL);
     }
 
-    if (!mz_zip_writer_add_to_central_dir(pZip, pContext->pArchive_name, (mz_uint16)pContext->archive_name_size, pContext->pExtra_data, (mz_uint16)pContext->extra_size, pContext->pComment, pContext->comment_size,
+    if (!mz_zip_writer_add_to_central_dir(pContext->pZip, pContext->pArchive_name, (mz_uint16)pContext->archive_name_size, pContext->pExtra_data, (mz_uint16)pContext->extra_size, pContext->pComment, pContext->comment_size,
                                           pContext->uncomp_size, pContext->comp_size, pContext->uncomp_crc32, pContext->method, pContext->gen_flags, pContext->dos_time, pContext->dos_date, pContext->local_dir_header_ofs, pContext->ext_attributes,
                                           pContext->user_extra_data_central, pContext->user_extra_data_central_len))
         return MZ_FALSE;
 
-    pZip->m_total_files++;
-    pZip->m_archive_size = pContext->cur_archive_file_ofs;
+    pContext->pZip->m_total_files++;
+    pContext->pZip->m_archive_size = pContext->cur_archive_file_ofs;
 
     return MZ_TRUE;
 }
diff --git a/src/miniz/miniz.h b/src/miniz/miniz.h
index cd647b9fa..8fe0461ad 100644
--- a/src/miniz/miniz.h
+++ b/src/miniz/miniz.h
@@ -1308,6 +1308,8 @@ typedef struct
 
 typedef struct mz_zip_writer_staged_context
 {
+    mz_zip_archive *pZip;
+
     mz_uint16  gen_flags;
     mz_uint    uncomp_crc32;
     mz_uint16  method;
@@ -1346,8 +1348,8 @@ typedef struct mz_zip_writer_staged_context
 mz_bool mz_zip_writer_add_staged_open(mz_zip_archive* pZip, mz_zip_writer_staged_context* pContext, const char* pArchive_name, 
     mz_uint64 max_size, const MZ_TIME_T* pFile_time, const void* pComment, mz_uint16 comment_size, mz_uint level_and_flags,
     const char* user_extra_data, mz_uint user_extra_data_len, const char* user_extra_data_central, mz_uint user_extra_data_central_len);
-mz_bool mz_zip_writer_add_staged_data(mz_zip_archive* pZip, mz_zip_writer_staged_context* pContext, const char* pRead_buf, size_t n);
-mz_bool mz_zip_writer_add_staged_finish(mz_zip_archive* pZip, mz_zip_writer_staged_context* pContext);
+mz_bool mz_zip_writer_add_staged_data(mz_zip_writer_staged_context* pContext, const char* pRead_buf, size_t n);
+mz_bool mz_zip_writer_add_staged_finish(mz_zip_writer_staged_context* pContext);
 
 /* Adds a file to an archive by fully cloning the data from another archive. */
 /* This function fully clones the source file's compressed data (no recompression), along with its full filename, extra data (it may add or modify the zip64 local header extra data field), and the optional descriptor following the compressed data. */