It's not complicated, just discard the first separator:

#! perl
use strict;

{
    $/ = "myrecordsep\n";
    scalar <DATA>; ##discard the first;
    while (<DATA>) {
        chomp;
        print "'$_'\n";
    }
}
__DATA__
myrecordsep
field1=item1
field2=item2
myrecordsep
field1=item1
field2=item2
myrecordsep
field1=item1
field2=item2
myrecordsep
field1=item1
field2=item2
[download]

Produces:

C:\test>junk2
'field1=item1
field2=item2
'
'field1=item1
field2=item2
'
'field1=item1
field2=item2
'
'field1=item1
field2=item2
'
[download]