Nothings makes me more curious than someone being secretive haha.
This is what Ethercat master documentation says
Two places to modify
Read out the sii info with "ethercat -p 0 sii_read"
1. Supported mailbox protocols.
Like it says in the figure, word 0x1C byte 0x38, bit 0x02 specifies EoE support.
Clear that bit for no support.
To orient yourself, you should find bit 3, 0x04, set for CoE support.
2. Enabled EoE mailboxes.
To find the byte that specifies drive EoE mailbox enabled:
In the read sii file, use some kind of hex editor.
Skip 0x80 bytes forward over the hardware config info
Byte 0x80-0x81 is 0x1a00 meaning strings section
Byte 0x82-0x83 is a word specifying the length of the string section.
Example : 0xd100 = 209(dec) words.
Add 1 to make it even: 210 words.
Multiply by 2 to make number of bytes: 420.
Add two for the size of the 0x1a00 identifier word: 422
Sum up 128 + 422 = 550. Hex 0x226
At bytes 0x226-0x227 one finds 0x1e00 meaning general information section
0x228-0x229 is a word specifying the length of the general section
EoE mailbox specifier is now byte 9 in this section: 0x231
To orient yourself, byte 8 (0x230) is FoE mailbox specifier, CoE details are in byte 7, (0x22f)
To disable EoE, first verify that the specified byte is 1. Then, write a zero in that position.
Upload the modified sii file to the drive again with "ethercat -p n sii_write mod_eeprom"
Personally, I wouldn't do this. I would use a Ethercat master with EoE disabled.
The above is only theoretical and may be wrong. Don't use it.