Is the Redmi AC2100 still worth buying? The 60-yuan laid-off machine was listed on Xianyu, and in one night, more than a dozen buyers asked, "Can I flash the phone?"

last month, my family's Redmi AC2100 officially retired. Its resume is quite complete: in the first few years it was the main router, then downgraded to a single 2.4G feed dedicated to smart devices, even that position was taken by the AX3600 that was bought for 95 yuan, . I casually set the price at 60 yuan and listed it on Xianyu, thinking that if it could be released, it would be released; if not, it would be restored and left for my relatives' kids to mess with. But overnight, more than a dozen messages flooded in, all surprisingly consistent: "Have you flashed your phone?" "Can I swipe it?" When I talked about the third buyer, I realized that this machine isn't sold as a router in the second-hand market, but as an introductory flashing guide.

clarify first: Xiaomi AC2100 and Redmi AC2100 are two separate machines

this step can discourage half the people who want to fall into the trap. The names of the two machines differ by only two characters, and they're often mixed up on Xianyu, but they don't even share the same chip solution.

Redmi AC2100, chassis model RM2100, black, six external antennas, MediaTek MT7621 platform; The Xiaomi AC2100 is that white box, with the antenna hidden inside the case, a Qualcomm platform. The firmware of the two devices is completely incompatible. If you flash a Xiaomi version into a Redmi version, it's very likely to become bricked directly. The flashing community only recognizes the Redmi version, because MediaTek has much more open-source materials, and a bunch of tutorials are available. The methods for saving bricks are also mature.

here's a lazy rule: you don't need to look at the bottom shell, just look at the photos. The six external antennas are vertically positioned, which is the Redmi version; The white square box with not a single antenna is visible—it's the Xiaomi version. The prices of the two are similar on Xianyu, but for flashing users, Redmi is the only option. The Xiaomi version has a Qualcomm chip with sporadic third-party firmware, so if you buy it, you can basically use it as a regular router. If you're rushing to flash, don't make a mistake.

So

the first thing before placing an order is to have the seller take a photo of the case and make sure to identify the five characters RM2100. If the seller can't even say which one they have, they just leave—this machine has been out of production for years, and there are quite a few mixed sources.

60 worth of veterans on second-hand hard currency

Redmi AC2100 was launched at the end of 2019, launching at 169 yuan. The slogan back then was 'Upgrade to 2000 Trillion for All,' and it sold like crazy. Looking at the specs today, it's basically entry-level: MT7621A dual-core, four-thread, 128MB RAM, 128MB flash storage, six 5dBi antennas, four 5G streams running at 1733Mbps, two 2.4G streams at 300Mbps, one WAN port plus three LAN ports for all Gigabit, and no USB ports.

it can still hold the strong 40 to 60 yuan price range in 2026, it's not about performance, but about ecosystem. The MT7621 platform has been fed by OpenWrt and Padavan for nearly ten years and is among the most mature supporters. Breed covers all brick rescue scenarios, and when you encounter problems, a quick search reveals the paths pioneers have taken before. For those who want to learn how to flash their phones, the 60 yuan trial-and-error cost is much cheaper than using your main home machine for repairs— I repeatedly said in my previous post AX3000T flashing OpenWrt, using a cheap machine first before switching to the main is the safest approach. The market is similar to the CR8809 that cost 95 yuan back then. the firmware flashed is 10 or 20 yuan more expensive, so it's better to save money and choose your own .

become the main router, it really won't hold up in 2026

pour cold water on anyone who wants to use it as the only router in their home. The wireless spec is WiFi 5, no WiFi 6. When a new phone connects to it, the negotiated top speed is 867Mbps. Face-to-face test results are around 500 Mbps, but after a wall is only 200 or 300 Mbps. Some people get excited when they see the specs for 5G with four streams at 1733Mbps. Calm down: four streams are for multi-device concurrent processing, while phones generally only have two streams. Negotiation is a drawback, and the extra two streams don't help a single phone at all. I've written about data on this for the data stream.

even more bottleneck-in is memory. 128MB is sufficient in 2019, but in 2026, when dozens of devices in the family are in use, it will be a struggle. During the two years when my home was the main router, whenever there were many smart devices, they would disconnect in bulk at midnight. finally cleared out the zombie devices, dismantled them, and dedicated them to feeding IoT devices before finally settled down. The cable side is quite good: four ports full gigabit, 100Mbps or 300Mbps broadband with closed-eye feeding, no problem running full.

conclusion is divided into two parts: 100Mbps broadband, rental apartments, dorms, and parents' homes are still sufficient today; Gigabit broadband combined with whole-home smart devices is the main slot—don't make things difficult for them.

buyers rush to buy it, they're fighting for the possibility of playing with it

chatting with those buyers, eight out of ten bought them to flash their phones. The process isn't complicated: first open the SSH gate under the official firmware. the official unlock channel for old machines is still alive, after entering, write Breed into the boot partition for a guaranteed minimum. If you want to flash Padavan or OpenWrt, switch however you like. Just flash it hard and start over in Breed. Before I sold my car, I deliberately restored it to the official original, leaving the process for the new owner to step on themselves—it's only fun to do it yourself.

how to choose between the two firmwares, in simple terms: Padavan is tailored for machines with small memory, light background runs, boots fast, and runs 128MB without breath; The OpenWrt plugin ecosystem is much larger, but its appetite for memory is also greater. On a 128MB machine, you only need to install two or three plugins and think twice. My suggestion is to first taste the benefits of Padavan. If you really need OpenWrt, then pay more for a machine with bigger memory, and don't force it on the veterans.

What can

do after farming? I've seen roughly three types of gameplay. First, install ad plugins; FamilyMart phones connected to this WiFi filter out one layer of ads by default; Second, when it acts as a side router, the main router stays still, and devices that need to be tampered with point the gateway over. If it breaks, unplugging the connection leaves no noticeable connection. my older Xiaomi Router 3 is already doing this role ; Third, provide some small service opportunities to practice hands-on. Some people even open up bandwidth and squeeze wireless after using Padavan, but this is subjective—stability and heat generation are your own backup.

to be clear in advance. 128MB of memory doesn't fit too many plugins, too much is bound to fail; The biggest flaw in flashing isn't the technical skill, but the mistaken flashing of the Xiaomi AC2100's firmware package into the Redmi version. That kind of thing can't be saved by Breed—you have to add TTL or even a programmer. the tragedy of that AC2100 brick brushing car not even turning on, I've recorded before. Before you start, check how others flipped the car—it can help you avoid many detours.

buy it for those who don't flash their phones, aiming for three simple jobs

the remaining 20% of buyers don't bother with it, buying it for being cheap, durable, and with clear job requirements.

Position One: Backup phones for rental apartments, dormitories, and the old home. A 60-yuan full gigabit port plus six antennas is more practical than brand-new small factory products at the same price point. It's not a waste to keep or give away when moving out. Position 2: IoT Private Network. I used it to send a single 2.4G device, dedicated to feeding slow devices like the vacuum cleaner, camera, and socket, separated from the mainline without interference—my last job was this one, and I managed a dozen devices steadily for over a year. Position 3: Secondary router for the home experimental network, learning to network and catch incidents, no worries if damaged.

conversely, if your home has gigabit broadband, dozens of smart devices, and phones all want WiFi6, it's better to save the 60 yuan and add some budget. just look at AX6S and other flashing ecosystem phones for around 100 yuan, or the brand-new BE3600—it's easier than reviving the veteran.

there's another question I've been asked twice: This machine has been out of production for several years, so how does it still have so much second-hand stock? The answer isn't complicated: the 169 yuan price was really sold at the time. Just ask around and you'll find a few shops have bought it, and the stock is obvious. Because of the large volume, you don't have to worry about parts breaking at all. Power supplies and antennas are sold separately on Xianyu platforms, which is why veterans are easier to maintain than niche machines.

four steps to inspect used machines, wrapping up with one form

you really want to buy it, follow this order: First, ask the system if it's original or officially flashed. If you want original, have the seller directly check the firmware version at 192.168.31.1; Step two: check the chassis: model RM2100, six antennas, not one missing, and no network port; Step three: test wired connection. Plug in the network cable and check if the negotiation requires 1000Mbps, and run a speed test; Step four: inventory the accessories—check if the power supply and network cables are missing. This is where you can bargain.

in the end: it's a router retired by the times and revived by players. 60 yuan won't be a loss, provided you think carefully about which position to place it in—as a textbook, it's a perfect score; It has been a mainstay for many years.