Random receive of 0x00 from EC25-E via uart

My EC25-E modules (FW EC25EFAR06A06M4G) more or less randomly send 0x00 bytes via the uart1 after command request.
For example during downloading a file from an FTP server. My code works as described in:
EC2x&EG9x&EG2x-G&EM05_Series_FTP(S)_Application_Note
page 43/53

AT+QFTPGET=“test_my.txt”,“COM:”
CONNECT

OK
+QFTPGET: 0,1000*

There randomly occures a 0x00 after CONNECT response.
This is specifically bad when downloading binary files, as 0x00 can be part of the file content
Do you have an idea how to tackle that?
in another thread i requestet firmware update toolset, but it would not hurt if you could send me a download link for EC25-E/EC25-EUX/EG25-G flash software plus newest firmware.
regards,
Alex

Hi,
The new firmware and upgrade tools have been sent to you, you can upgrade and try again.