Warning: i86bi-linuxl2-adventerprisek9-m-152-may-2018.bin is a Cisco IOS binary (proprietary). You must have a valid Cisco software license and entitlement (e.g., a service contract or support agreement) to download and use it legally. Do not attempt to download this image from unauthorized sites.
Some users report duplex issues with older 15.2 images. This May 2018 build is generally more stable, though you should verify that your virtual interfaces aren't defaulting to half-duplex. Legal Note: i86bi-linuxl2-adventerprisek9-m-152-may-2018.bin download
However, directly providing or asking for a download link for specific software images can sometimes be problematic due to copyright and licensing restrictions. Cisco Systems, Inc. typically requires users to have a valid account and often imposes strict controls over the distribution and use of their software images. Warning: i86bi-linuxl2-adventerprisek9-m-152-may-2018
