RT-AC66U-B1 Difference between HW Ver: A1 and B1

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Gigabyte

New Around Here
What is the difference between the RT-AC66U-B1 HW Ver: A1 and B1? Would like to run Tomato by Shibby or Merlin if it matters.

Tried Googling and searching the forums but ASUS makes things very difficult by reusing the same names and putting A1 and B1 on everything. They're as bad as Porsche. I emailed their tech support but I'm not getting my hopes up. Hoping someone has done the research here and can share.



My old RT-N66U Dark Knight died so the HW Ver B1 WiFi key is fitting.
 

jtc242

New Around Here
I am very interested in the answer. FWIW I have an A1 HW Version and was not able to find a compatible tomato firmware. I was able to flash it with ASUSWRT-Merlin by using the RT-AC68U firmware.
 

Blinkyz

Senior Member
the difference between the RT-AC66U-B1 HW Ver: A1 and B1?
A1 =CPU1: Broadcom BCM4706 (600 MHz) cpu
B1 =CPU1: Broadcom BCM4708C0 (800 MHz, 2 cores) , this one use the same fw as Ac68U
 

Gigabyte

New Around Here
the difference between the RT-AC66U-B1 HW Ver: A1 and B1?
A1 =CPU1: Broadcom BCM4706 (600 MHz) cpu
B1 =CPU1: Broadcom BCM4708C0 (800 MHz, 2 cores) , this one use the same fw as Ac68U
Are you sure about the A1? I'm currently using it and Core 1 and Core 2 are listed under system status with different usage percentages.
 

bbunge

Very Senior Member
You need to be careful with these routers. The RT-AC66U_B1 is not the same as a RT-AC66U.
My RT-AC66U_B1 has a H/W Ver. :A1, A dual core 1000 MHz processor and can be flashed with Merlin firmware for the RT-AC68U. Also has one front USB3 port
The RT-AC66U is a single core processor with two USB2 back ports and uses a different firmware from the model RT-AC66U_B1
Would be interesting to see what the difference is between the RT-AC66U_B1 H/W Ver A1 and RT-AC66U_B1 H/W Ver B1 as I've had some issues with the USB3 port on my router and am currently at F/W Ver 3.0.0.4.380_4164 per recommendation from Asus tech support. Am waiting for the 3.0.0.4.380_7378 firmware to see if it resolves my "issues."
 

Gigabyte

New Around Here
You need to be careful with these routers. The RT-AC66U_B1 is not the same as a RT-AC66U.
My RT-AC66U_B1 has a H/W Ver. :A1, A dual core 1000 MHz processor and can be flashed with Merlin firmware for the RT-AC68U. Also has one front USB3 port
The RT-AC66U is a single core processor with two USB2 back ports and uses a different firmware from the model RT-AC66U_B1
Would be interesting to see what the difference is between the RT-AC66U_B1 H/W Ver A1 and RT-AC66U_B1 H/W Ver B1 as I've had some issues with the USB3 port on my router and am currently at F/W Ver 3.0.0.4.380_4164 per recommendation from Asus tech support. Am waiting for the 3.0.0.4.380_7378 firmware to see if it resolves my "issues."
Yes, I would like to keep this thread specifically about the RT-AC66U-B1 HW Ver: A1 and HW Ver: B1. I loaded Merlin firmware on the HW Ver: B1 and it seems to have the same CPU as the HW Ver: A1. You should check for updates using the web GUI. The A1 updated to 3.0.0.4.380_7378 the first time I plugged it in and checked last night.

 
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bbunge

Very Senior Member
Interesting about your update. I just checked the Asus US web site again and ran the FW check on the router and they both said Firmware version 3.0.0.4.380_7266-g6439257 is available. What country are you in? Are you having any issues with Adaptive QOS?

My intent in talking about the plane AC66U and the AC66U_B1 model was to, again, flag that there is a difference between them.
 

Gigabyte

New Around Here
That stinks. I'm in Boston. I noticed the website only had 3.0.0.4.380.7266 when I was grabbing backups before flashing the firmware earlier. Guess I'll just tease you with this for now.



I knew what you meant and wanted to highlight it again. It was a good catch. Don't want anyone bricking their router. ASUS makes this very confusing.
 

bbunge

Very Senior Member
That stinks. I'm in Boston. I noticed the website only had 3.0.0.4.380.7266 when I was grabbing backups before flashing the firmware earlier. Guess I'll just tease you with this for now.



I knew what you meant and wanted to highlight it again. It was a good catch. Don't want anyone bricking their router. ASUS makes this very confusing.
Well, my neighbor still speaks with a funny Boston accent... I was stationed there in the early 70's and found the natives friendly...
You flashed it with the AC68U "official" firmware? I suspect it would not hurt it as at least one part of the AC66U_B1 firmware (AIProtection test email) says AC68U!
 

Gigabyte

New Around Here
It took a little while to get used to the accents here. They don't hold being from NY against me too much and are very nice.

HW ver B was flashed to Merlin firmware. Wanted ASUS firmware as a backup in case I ran into issues and needed to restore.

HW ver A1 upgraded itself to 3.0.0.4.380_7378 in the screenshot above. I don't remember if I was prompted during the initial router setup or if I checked Advanced Settings > Administration > Firmware Upgrade immediately after the initial setup.


I received a response from ASUS. I had low expectations but this is even worse than anticipated.

"It's just two different Version of the same router with a slightly different firmware and one being produced before the other

Best Regards,
Andrea M.

ASUS Technical Support
http://www.asus.com/us/support/"

My original question was "What is the difference between the

RT-AC66U-B1 HW Ver: A1 and
RT-AC66U-B1 HW Ver: B1

Production year 2016 for both."
I attached the two photos from my OP too. Wish ASUS would tell us the difference and stop mixing hardware, model numbers and firmware like this.
 

RMerlin

Asuswrt-Merlin dev
I attached the two photos from my OP too. Wish ASUS would tell us the difference and stop mixing hardware, model numbers and firmware like this.
Sometimes, the differences are purely manufacturing-wise. They could have added a capacitor here, replaced a memory chip by a newer/less expensive one, etc...

That type of information is rarely known by the technical support department, as they have zero impact on the end users.
 

bbunge

Very Senior Member
It took a little while to get used to the accents here. They don't hold being from NY against me too much and are very nice.

HW ver B was flashed to Merlin firmware. Wanted ASUS firmware as a backup in case I ran into issues and needed to restore.

HW ver A1 upgraded itself to 3.0.0.4.380_7378 in the screenshot above. I don't remember if I was prompted during the initial router setup or if I checked Advanced Settings > Administration > Firmware Upgrade immediately after the initial setup.


I received a response from ASUS. I had low expectations but this is even worse than anticipated.

"It's just two different Version of the same router with a slightly different firmware and one being produced before the other

Best Regards,
Andrea M.

ASUS Technical Support
http://www.asus.com/us/support/"

My original question was "What is the difference between the

RT-AC66U-B1 HW Ver: A1 and
RT-AC66U-B1 HW Ver: B1

Production year 2016 for both."
I attached the two photos from my OP too. Wish ASUS would tell us the difference and stop mixing hardware, model numbers and firmware like this.
Still can find only the 380.7266 FW on the Asus USA web site for the AC66U_B1. So I did the unthinkable and flashed the 380.7378 for the AC68U. Since Merlin's version for the AC68U works on the AC66U_B1 I calculated it would work and it does! Still have mixed up Bandwidth Monitor values with IPV6 (6RD) enabled and Adaptive QOS issues when using Manual entries. But I had those with the original and Merlin FW.
BTW - I'm originally from Western NY and the folks in Southern PA still think I talk funny (Is it creek or crick?)
 

RMerlin

Asuswrt-Merlin dev
Still can find only the 380.7266 FW on the Asus USA web site for the AC66U_B1. So I did the unthinkable and flashed the 380.7378 for the AC68U.
They are exactly the same firmware. Asus does not compile different versions for these two models.
 

Gigabyte

New Around Here
Sometimes, the differences are purely manufacturing-wise. They could have added a capacitor here, replaced a memory chip by a newer/less expensive one, etc...

That type of information is rarely known by the technical support department, as they have zero impact on the end users.
That's why good technical support departments escalate incidents and inquirers to more knowledgeable departments. I should have known this was going to be a headache after reading Tomato by Shibby's Router List "Hardware Rev C1 is not supported!", dozens of T-Mobile TM-AC1900 threads and what little I could find on the RT-AC66U. The RT-AC66U-B1 HW Ver: ABCDEFG1 is picking up where they left off. Fortunately there's plenty of time for me to shop around and return these headaches.

Still can find only the 380.7266 FW on the Asus USA web site for the AC66U_B1. So I did the unthinkable and flashed the 380.7378 for the AC68U. Since Merlin's version for the AC68U works on the AC66U_B1 I calculated it would work and it does! Still have mixed up Bandwidth Monitor values with IPV6 (6RD) enabled and Adaptive QOS issues when using Manual entries. But I had those with the original and Merlin FW.
BTW - I'm originally from Western NY and the folks in Southern PA still think I talk funny (Is it creek or crick?)
I put the ASUS default 66U firmware back on the B1 prior to returning it and it did not update to 380.7378 automagically. Manually upgrading to the AC68U's 380.7378 worked. Found the following in the System Log > General Log. Everything else looks the same.

HW Ver: B1 - Aug 1 00:00:17 kernel: Found a Zentel NAND flash:
HW Ver: A1 - Aug 1 00:00:17 kernel: Found a AMD NAND flash:
 

RMerlin

Asuswrt-Merlin dev
That's why good technical support departments escalate incidents and inquirers to more knowledgeable departments.
In this case, we're not talking about an incident, but about someone asking information about manufacturing decisions.
 

osi19

New Around Here
The one i have ordered 3 days ago was RT-AC66U without label B1. But today i am receiving the newest version B1 with hw B1 and dual core processor. I am quite happy about that. The biggest CONS of this version is the undetachable antennas, otherwise i am receiving dual core processor and usb 3.0
RT-AC66U B1 ed.jpg
• ASUS RT-AC66U B1 H/W Ver.:A1 - BCM4708C0 (@1.0GHz Dual Core)

Also has one front USB3 port, one USB2 back ports, AMD flash (NAND),
and can be flashed with Merlin firmware for the RT-AC68U.
• ASUS RT-AC66U B1 H/W Ver.:B1 - BCM4708C0 (@1.0GHz Dual Core)

Also has one front USB3 port, one USB2 back ports, Zentel flash (NAND).
ASUS RT-AC66U - BCM4706 (@600MHz Single Core), two USB2 back ports.
 
Last edited:

medwatt

Regular Contributor
The one i have ordered 3 days ago was RT-AC66U without label B1. But today i am receiving the newest version B1 with hw B1 and dual core processor. I am quite happy about that. The biggest CONS of this version is the undetachable antennas, otherwise i am receiving dual core processor and usb 3.0
View attachment 9858
• ASUS RT-AC66U B1 H/W Ver.:A1 - BCM4708C0 (@1.0GHz Dual Core)

Also has one front USB3 port, one USB2 back ports, AMD flash (NAND),
and can be flashed with Merlin firmware for the RT-AC68U.
• ASUS RT-AC66U B1 H/W Ver.:B1 - BCM4708C0 (@1.0GHz Dual Core)

Also has one front USB3 port, one USB2 back ports, Zentel flash (NAND).
ASUS RT-AC66U - BCM4706 (@600MHz Single Core), two USB2 back ports.
I got the same one. Install Asuswrt-Merlin and be done with it.
 

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