Asus uses Tomato-derived Firmware with the name Asuswrt for its newer routers, such as the RT-AC87 and RT-AC5300. This firmware is, with the exception of a few drivers, open source, with the closed binaries being delivered. Asuswrt-merlin is in turn a modified version of the original firmware of Asus. It includes bugfixes and minor improvements, but still tries to stay close to the original, so that it is possible to add new features that Asus introduces to the code.

With Asuswrt-Merlin 382, ​​the team started from scratch with a clean 382 firmware from Asus. It turned out to be too difficult to transfer the changes from version 380 to version 382. At the moment it does not work with all models yet. The release notes for this issue are as follows:

Note:
Asus has put the RT-AC56U on their End of Life list, meaning no further firmware releases from them. Since it’s impossible for me to support models without matching GPL releases from Asus, I also have the RT-AC56U. 384.6 is the final release for that model.
The RT-AC3200 and RT-AC87U are not supported by this release, Asus has not released any updated code yet for these models.
New:
Added RT-AX88U support (based on GPL 384_4736).
Merged with GPL + binary blobs from 384_32799 (all supported models except RT-AX88U)
Add LZ4 V2 option to OpenVPN compression (more effective at handling already compressed data)
Added “extend” support to SNMP.
Added CleanBrowsing to DNSFilter supported services.
Webui HTTP LAN port can now be changed from the default 80.
Added support for the Netfilter TEE target.
Changed:
Removed watchdog from OpenVPN clients, to avoid conflicting with more advanced configurations.
Vsftpd TLS mode will now reuse the web server certificate (including any Let’s Encrypt generated one).
SSL crypto / cipher hardening for httpd (themiron)
Syslog will now ignore bwdpi debug output (themiron)
Reworked Wireless Log page, low-level details (what stock firmware shows on the Wireless Log page), and removed redundant option to display DFS channel details.
Update dnsmasq to 2.80-11-g59e4703 (themiron)
Updated nettle to 3.4
Updated net-snmp to 5.8
Updated openssl to 1.0.2q
Migrated / jffs / ssl / * content to / jffs /.cert (to share the same folder used by Asus stock)
Re-enabled WTFast on non-HND models (curl-related crash has been fixed). This is still untested.
Updated CA bundle to October 17th 2018 version.
Support search domains pushed by a remote OpenVPN server
Fixed:
UOPNP port forwarding not working in CGNAT / double NAT scenario even if clean ports were forwarded upstream.
Pages based on table.js (like the port trigger one) would fail to work properly under Firefox (Michael Ziminsky)
Dnsmasq issues when running in non-router mode (John Bacho)
Routing issues when in non-router mode (John Bacho)
Bug in curl that could cause some applications to crash on non-HND models
IFTTT failing to start on non-HND models (caused by curl issue).
Webui could complain about port 8080 being reserved for http WAN port (which is no longer supported)
Can not change image for device with a vendor name containing an apostrophe (like Micro-Star int’l) (Asus bug)
OpenVPN client download was capped by Adaptive QOS upload limit (fix devised by FreshJR)
OpenVPN custom config could be solved after a reboot on the RT-AC86U.
Asuswrt-Merlin screenshot (810 pix)

Version number 384.8
Release status Final
Website
Asuswrt-Merlin
Download
https://sourceforge.net/projects/asuswrt-merlin/files/
License type GPL