Meraki
March 24, 2026
MerakiMR18RouterJTAGOpenWrt
The last mile: a PHY bug, a 20-minute serial transfer, and victory
We made it, yeah, we made it
Last post ended with failsafe mode running but Ethernet RX completely broken. TX works—the MR18 sends ARP requests just fine—but it can’t receive a single packet. Every incoming frame triggers FCS errors. rx_packets is zero. Ping doesn’t work because ARP replies from the host never reach the device.
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March 24, 2026
MerakiMR18RouterJTAGOpenWrt
I know you’re somewhere out there, somewhere far away
Okay so the kernel booted. Like actually booted. I saw Linux version 6.6.73 scroll across the UART console. The CPU was running, the scheduler was active, idle task spinning. I set up my host Ethernet at 192.168.1.2/24, pointed my browser at 192.168.1.1, and… nothing. Ping? Nothing. Telnet? Nothing. ARP? Nothing.
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March 24, 2026
MerakiMR18RouterJTAGOpenWrt
The cache coherency nightmare and other fun MIPS things
I been goin’ through some things, I was pourin’ and the Henny
So last post ended with the binary loaded, the CPU launched, and data error! on the serial console. The lzma-loader—the little decompressor that’s supposed to unpack our kernel—was choking on the LZMA stream. The binary I loaded was correct (I verified the MD5 before loading), the ath79 build was the right one, the address was correct. What the fuck.
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March 24, 2026
MerakiMR18RouterJTAGOpenWrt
Everything is wired up, let’s flash
She said, “Where we goin’?” I said, “The moon”
Alright so we left off with all the wires connected, the bench power supply ready, and my ESP-Prog looking like a spaghetti monster grew on my desk. Time to actually make this thing do something.
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March 24, 2026
MerakiMR18RouterJTAGOpenWrt
I mean, where the fuck should I really even start?
I got hoes that I’m keepin’ in the dark
Okay, but really though, where do I start? Right now we know that the Meraki MR18 is cloud-locked by Cisco. Without an active Meraki dashboard license there are many niceties that I don’t have access to such as:
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March 24, 2026
MerakiMR18RouterJTAGOpenWrt
This is my first blog—I am not very proficient in writing, especially not technical writing and my grammar sucks, but hey who cares. I will have a series of posts talking about how I managed to install OpenWrt on a Meraki MR18 access point. I will try to explain things as I go to not leave readers in the dark, but some background technical understanding/ability to research more in-depth confusing topics will greatly help the reader.
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