diff --git a/examples/08-update/update.cpp b/examples/08-update/update.cpp
index 7df60411a..cb1dd74e1 100644
--- a/examples/08-update/update.cpp
+++ b/examples/08-update/update.cpp
@@ -185,6 +185,15 @@ bgfx::TextureHandle loadTextureWithUpdate(const char* _filePath, uint64_t _flags
 					width  = bx::max(blockWidth,  width);
 					height = bx::max(blockHeight, height);
 
+					// Compute source row pitch and pass it to updateTexture2D to
+					// exercise the explicit-pitch upload path.
+					const uint32_t numBlocksX = (width + blockWidth - 1) / blockWidth;
+
+					const uint32_t srcPitch = bimg::isCompressed(imageContainer->m_format)
+						? numBlocksX * blockInfo.blockSize
+						: width * blockInfo.bitsPerPixel / 8
+						;
+
 					bimg::ImageMip mip;
 
 					if (bimg::imageGetRawData(*imageContainer, 0, lod, imageContainer->m_data, imageContainer->m_size, mip))
@@ -201,6 +210,7 @@ bgfx::TextureHandle loadTextureWithUpdate(const char* _filePath, uint64_t _flags
 							, uint16_t(width)
 							, uint16_t(height)
 							, bgfx::copy(mipData, mipDataSize)
+							, uint16_t(srcPitch)
 							);
 					}
 
diff --git a/src/renderer_gl.cpp b/src/renderer_gl.cpp
index b182ceca1..d98bdf9d5 100644
--- a/src/renderer_gl.cpp
+++ b/src/renderer_gl.cpp
@@ -6003,8 +6003,11 @@ namespace bgfx { namespace gl
 
 	void TextureGL::update(uint8_t _side, uint8_t _mip, const Rect& _rect, uint16_t _z, uint16_t _depth, uint16_t _pitch, const Memory* _mem)
 	{
+		const bimg::ImageBlockInfo& blockInfo = bimg::getBlockInfo(bimg::TextureFormat::Enum(m_requestedFormat) );
+		const bool compressed = bimg::isCompressed(bimg::TextureFormat::Enum(m_requestedFormat) );
 		const uint32_t bpp = bimg::getBitsPerPixel(bimg::TextureFormat::Enum(m_textureFormat) );
-		const uint32_t rectpitch = _rect.m_width*bpp/8;
+
+		uint32_t rectpitch = _rect.m_width*bpp/8;
 		uint32_t srcpitch  = UINT16_MAX == _pitch ? rectpitch : _pitch;
 
 		GL_CHECK(glBindTexture(m_target, m_id) );
@@ -6021,7 +6024,6 @@ namespace bgfx { namespace gl
 			&& !s_renderGL->m_textureSwizzleSupport
 			;
 		const bool unpackRowLength = !!BGFX_CONFIG_RENDERER_OPENGL || s_extension[Extension::EXT_unpack_subimage].m_supported;
-		const bool compressed      = bimg::isCompressed(bimg::TextureFormat::Enum(m_requestedFormat) );
 		const bool convert         = false
 			|| (compressed && m_textureFormat != m_requestedFormat)
 			|| swizzle
@@ -6038,13 +6040,23 @@ namespace bgfx { namespace gl
 		uint32_t width  = rect.m_width;
 		uint32_t height = rect.m_height;
 
+		if (compressed
+		&& !convert)
+		{
+			const uint32_t numBlocksX = (width + blockInfo.blockWidth - 1) / blockInfo.blockWidth;
+			rectpitch = numBlocksX * blockInfo.blockSize;
+			srcpitch  = UINT16_MAX == _pitch ? rectpitch : _pitch;
+		}
+
 		uint8_t* temp = NULL;
 		if (convert
-		||  !unpackRowLength)
+		||  !unpackRowLength
+		||  (compressed && UINT16_MAX != _pitch && srcpitch != rectpitch) )
 		{
 			temp = (uint8_t*)bx::alloc(g_allocator, rectpitch*height);
 		}
-		else if (unpackRowLength)
+		else if (unpackRowLength
+		     &&  !compressed)
 		{
 			GL_CHECK(glPixelStorei(GL_UNPACK_ROW_LENGTH, srcpitch*8/bpp) );
 		}
@@ -6054,9 +6066,11 @@ namespace bgfx { namespace gl
 		{
 			const uint8_t* data = _mem->data;
 
-			if (!unpackRowLength)
+			const uint32_t numBlocksY = (height + blockInfo.blockHeight - 1) / blockInfo.blockHeight;
+
+			if (NULL != temp)
 			{
-				bimg::imageCopy(temp, width, height, 1, bpp, srcpitch, data);
+				bimg::imageCopy(temp, numBlocksY, srcpitch, 1, data, rectpitch);
 				data = temp;
 			}
 			const GLenum internalFmt = (0 != (m_flags & BGFX_TEXTURE_SRGB) )
@@ -6072,7 +6086,7 @@ namespace bgfx { namespace gl
 				, rect.m_height
 				, _depth
 				, internalFmt
-				, _mem->size
+				, rectpitch*numBlocksY
 				, data
 				) );
 		}
diff --git a/src/renderer_vk.cpp b/src/renderer_vk.cpp
index f9c9e8df5..bf7b33697 100644
--- a/src/renderer_vk.cpp
+++ b/src/renderer_vk.cpp
@@ -6933,21 +6933,43 @@ retry:
 
 		const uint32_t bpp = bimg::getBitsPerPixel(bimg::TextureFormat::Enum(m_textureFormat) );
 		const bimg::ImageBlockInfo& blockInfo = bimg::getBlockInfo(bimg::TextureFormat::Enum(m_textureFormat) );
-		uint32_t rectpitch = _rect.m_width * bpp / 8;
+		const bool compressed = bimg::isCompressed(bimg::TextureFormat::Enum(m_textureFormat) );
+		const bool convert    = m_textureFormat != m_requestedFormat;
+
+		uint32_t rectpitch  = _rect.m_width * bpp / 8;
 		uint32_t slicepitch = rectpitch * _rect.m_height;
-		uint32_t align = blockInfo.blockSize;
-		if (bimg::isCompressed(bimg::TextureFormat::Enum(m_textureFormat) ) )
+		uint32_t numRows    = _rect.m_height;
+		uint32_t align      = blockInfo.blockSize;
+		if (compressed)
 		{
-			rectpitch  = (_rect.m_width  / blockInfo.blockWidth ) * blockInfo.blockSize;
-			slicepitch = (_rect.m_height / blockInfo.blockHeight) * rectpitch;
+			const uint32_t numBlocksX = (_rect.m_width  + blockInfo.blockWidth  - 1) / blockInfo.blockWidth;
+			const uint32_t numBlocksY = (_rect.m_height + blockInfo.blockHeight - 1) / blockInfo.blockHeight;
+			rectpitch  = numBlocksX * blockInfo.blockSize;
+			slicepitch = numBlocksY * rectpitch;
+			numRows    = numBlocksY;
 		}
+
 		const uint32_t srcpitch = UINT16_MAX == _pitch ? rectpitch : _pitch;
-		const uint32_t size     = UINT16_MAX == _pitch ? slicepitch  * _depth: _rect.m_height * _pitch * _depth;
-		const bool convert = m_textureFormat != m_requestedFormat;
+		const uint32_t size = convert || UINT16_MAX == _pitch
+			? slicepitch * _depth
+			: numRows * srcpitch * _depth
+			;
+
+		// bufferRowLength is expressed in texels and, for block-compressed
+		// formats, must be a multiple of the block width.
+		uint32_t bufferRowLength = 0;
+		if (!convert
+		&&  UINT16_MAX != _pitch)
+		{
+			bufferRowLength = compressed
+				? (srcpitch / blockInfo.blockSize) * blockInfo.blockWidth
+				: srcpitch * 8 / bpp
+				;
+		}
 
 		VkBufferImageCopy region;
 		region.bufferOffset      = 0;
-		region.bufferRowLength   = (_pitch == UINT16_MAX ? 0 : _pitch * 8 / bpp);
+		region.bufferRowLength   = bufferRowLength;
 		region.bufferImageHeight = 0;
 		region.imageSubresource.aspectMask     = m_aspectFlags;
 		region.imageSubresource.mipLevel       = _mip;