yes you can, thats why I left the old code available in the spoiler at the bottom.
But I think the new code is fast enough that it will probably do fine anyway.

hello,

I tested your code I get an error E1513 when copying the file in the function file_void_insert at the line memcpy( buffer1+bytepos , block, block_size); //copy across insert data

thankss you for your code !

I cant see a way for it to fail there.

Can you post the code (and a descritpion of the file & data) that killed it?

hello,

here my code :

thanks in advance to say what's wrong !

The crash is because you arent giving "file_str_insert" a string.
When you trying to call it like this
file_str_insert(RW_file,"A",1,1);
then you are only giving it a single byte of type "CHAR" when it needs a "STRING" type.

To achieve this simply, callthe function like so
file_str_insert(RW_file, _str("A") ,1,1);
will give the function a temporary string, which is good enough...