Under Windows8.1 with ext reader software like Paragon ExtFS I can read/WRITE but not DELETE files from the ext partition. ext2Mgr can not Access the partition at all. Reader Software like Linux Reader, ext2explore can read it
I tried it with a 4GB normal microSD and a 64GB SDXC. The micro SD is inserted into 2 different USB-readers (one with an SD2microSD adapter), one which can direct read microSD and on another PC into an built-in reader with an microSD to SD Adapter. Files and Partition have read/write permisions fr everyone.