It displays your cookie file which should look something like this:
04 ff c3 06 00 1e 4a 8c 7d d1 43 00 22 c1 8b 46 4f 43 31 30 31 32 33 4d 4a 30 40 04 1b 41 06 00 82 49 1f ff 07 42 41 30 c0 46 03 20 00 5b 8a 04 88 00 00 00 00 02 04 c6 8a 49 50 4d 37 52 30 30 43 52 41 03 00 81 00 00 00 00 04 00 cb 89 43 49 53 43 4f 11 38 34 31 89 56 30 33 20 d9 02 c1 40 09 86 c2 8b 46 48 4b 31 30 31 35 33 30 38 48 ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
with more FFs at the end to fill the eprom.
Notice the extra spaces in the middle. Ive added them to help later but they arent shown in the cookie readout.
You might notice your first line looks like this:
04 ff 09 86 ff ff ff ff ff ff ff ff ff ff ff ff
Basically your MAC addresses for your cookies are corrupted so you will need to fix and replace the middle 6 pairs, and change the rest to reflect this table
04 ff 09 86 "ff ff ff ff ff ff" 43 00 22 c1 8b 46
Where those FFs are change them to something else, You can use these:
00 1e 4a 8c 7d d1
Ok So how do i change it?
With your calculator add 2 pairs together as such:
04ff + 0986 + ffff + ffff + ffff + ffff + ffff + ffff = 60e7f
Some guide say to do the first 5 pars but you will need to do all of them. Then drop the leading number to give you 0e7f. This is your priv password.
In Rommon type “priv” and enter the password. You will know it if works by giving you a warning prompt. If it doesnt, nothing will happen.
Now to correct the cookie. Type in “cookie” again and it will give you the first line to edit. Remember how i seprerated the cookie in half at the top of the post? Each half is a line. Change the cookie to match what you want, entering spaces between values. When you have finished the lines that you want to change just enter through the rest. Then type reset or boot. Hopefully that fixes that there. But if you made a mistake entering in your cookie you will have to go through the process again and will have to calculate another cookie password.
So what you you are unlucky like me and got a message saying that your hardware might not be genuine and it just boots straight to rommon again with a message of “Failed Identification Test in 0/-1/-1 [7/0]”?
Easy, open up your router and find the tiny white sticker on the PCB. This will give you your serial number. Use your phone as a magnifying glass as I did, my eyes were getting pretty sore by then. It should look like this one “FOC14062RR7” You will have to convert ASCII and you will get a result like this:
46 4f 43 31 34 30 36 32 52 52 37
Enter down though to line “bytes 0x10-0x17” (making sure not to change anything by not typing any text) and start from 4f and enter the 8 pairs for that line. The 46 should be the last entry from the previous line. The next line enter the last 2 pairs and copy the rest as they were.
My first few lines looks like this
04 ff c3 06 00 1e 4a 8c
7d d1 43 00 22 c1 8b 46
4f 43 31 30 31 32 33 4d
4a 30 40 04 1b 41 06 00
82 49 1f ff 07 42 41 30
c0 46 03 20 00 5b 8a 04
Hopefully this should fix your dramas. For more infor check out this:
I hope this helps any other poor soul that falls down this rabbit hole
EDIT: Note that some of these values are specific to my router so changing them to match mine wont help completely, also cross reference with a few different sources of sample 1841 cookies to make sure i havent made a mistake coping things down. I checked and rechecked by finding common values from a number of cookies. You can always enter rommon again and change something you dont think is right