After six months of flashing ImmortalWrt on K3: I clearly explained all three aspects: memory usage, temperature, and stability with all plugins enabled

have been quite busy at home lately and have fallen into quite a few pitfalls, so I decided to record the process. It would be best if it could help others with similar problems.

I previously wrote in detail about this in the article on Phicomm K3 Disassembly and Cooling , and the methodology is universal. Today's post covers the new pitfalls I've made.

By the way, there's another related articleOpenWrt Must-Read Before Flashing, Reading Together for a More Complete Look.

my K3 status: hardware modifications

This K3 was bought during the 2018 mining disaster. The hardware was changed in three ways: 256MB NAND (originally 128MB), a 12V silent fan (changed from 5V to 12V to prevent burnout, later lowered to 7V with an LM2596 buck board), and a spare SSD connected to the USB port to use as a lightweight NAS. After the cooling upgrade, the temperature dropped from 78°C to 52°C, so long-term driving is no problem.

ImmortalWrt vs the original OpenWrt, why I chose Immortal

OpenWrt Official support for Broadcom chips has always been an issue; the K3's BCM4366E uses closed-source drivers, resulting in a much weaker 5G signal. This fork for ImmortalWrt integrates the MT76 replacement driver, some Chinese optimizations, and precompiled K3 firmware, making it much more user-friendly for domestic users. I'm using ImmortalWrt 21.02.3 K3 custom edition, rootfs 64MB.

10 plugins are open, and the memory usage is as follows

free -m runs: total 247MB, used 138MB, free 78MB, buff/cache 31MB. Installed: SQM QoS, PassWall (subscription link import), Turbo ACC network acceleration, SmartDNS, AdGuardHome, DDNS, Upnp, traffic monitoring, file sharing (Samba), FRPC intranet traversal. When idle, used speeds stabilize around 130MB, and when switching PassWall nodes, it can instantly spike to 180MB. After running all night, it's stable without OOM. The K3's memory, according to the official statement, 256MB is the limit. In actual tests, it can hold up, but don't add more.

Temperature and Stability: Six months without restarting

thermal_zone0 Probe readings: CPU 49-55°C (with fan), 2.4G chip 62°C, 5G chip 71°C. The fan is scheduled to turn off at night from 22:00 to 07:00, and even when the fan is off, the CPU can reach 65°C steadily. After six months, reboot once: manually update the firmware. Other times are stable, with an average online stay of 89 days, and the most recent uptime is 21 days remaining. The only thing to note is that in summer, when the room temperature exceeds 30°C, it's recommended to set the fan to a normal setting. I set the temperature control threshold to 70°C to start.

sum it up in one sentence: before you start, lower your expectations. If you encounter a pitfall, record it first and then look back. Don't try to finish everything at once. I only stabilized after three rounds of revisions. The process was quite tough, but I gained something every time.