Encountered an Invalid block size error while using client.download()

[M1chaelWang]

download_data = bytearray(40) err_code = client.download(download_data, 3)
When running this line of code, the program threw an "Invalid block size" error and I can't figure why.
Please I need help. THX!!! :)

[gijzelaerr]

Closing as stale. The download() function expects properly formatted S7 block data with valid block headers, not arbitrary bytearrays.