Both iOS device and Android devices are not compatible with SP-404SX Wave Converter.
You can use it with Windows or macOS. https://www.roland.com/global/products/sp-404sx/downloads/
Note: Compatibility differs depending on the OS version or the spec of your computer. For more information, please refer to Support News. https://www.roland.com/global/support/
You can import audio files from an SD card without using the included “SP-404SX Wave Converter”
software. For more instructions, please refer to the related article “SP-404SX: Importing Samples.”
Note: You need an SD card that has been formatted by the SP-404SX. If you’re using the SD card that was included with the SP-404SX, don’t format the card.