U-boot Auto Boot Challenge: Seeking Assistance for OpenWRT Installation on Meraki MR16

Greetings everyone! :wave: I'm currently in the process of installing OpenWRT on a Meraki MR16 using the DSD TECH SH-U09C USB to TTL Serial Adapter with the FTDI FT232RL chip, from a Linux PC using Minicom. The connection has been successfully established by connecting the pins, but I'm facing a challenge—I'm unable to interrupt the U-boot Auto Boot process. It seems that the waiting period to press any key is disabled.

Does anyone have any suggestions or insights on how I can resolve this issue? Is it possible to extend the timeout to stop the Auto Boot? I would greatly appreciate any help or shared experiences in this process! :pray: #OpenWRT #MerakiMR16 #Uboot #Linux #TechnicalHelp

Boot Sequence:

U-Boot 1.1.4-g5416eb09-dirty (Mar 3 2011 - 16:28:15)

AP96 (ar7100) U-boot 0.0.1 MERAKI
DRAM: b8050000: 0xc0140180
64 MB
Top of RAM usable for U-Boot at: 84000000
Reserving 228k for U-Boot at: 83fc4000
Reserving 192k for malloc() at: 83f94000
Reserving 44 Bytes for Board Info at: 83f93fd4
Reserving 36 Bytes for Global Data at: 83f93fb0
Reserving 128k for boot params() at: 83f73fb0
Stack Pointer at: 83f73f98
Now running in RAM - U-Boot at: 83fc4000
id read 0x100000ff
flash size 16MB, sector count = 256
Flash: 16 MB
In: serial
Out: serial
Err: serial
Net: ag7100_enet_initialize...
ATHRF1E: Port 0, Neg Success
ATHRF1E: unit 0 phy addr 0 ATHRF1E: reg0 1000
eth0: 00:03:7f:e0:00:62
eth0 up
No valid address in Flash. Using fixed address
ATHRF1E: Port 1, Negotiation timeout
ATHRF1E: unit 1 phy addr 1 ATHRF1E: reg0 ffff
eth1: 00:03:7f:09:0b:ad
eth1 up
eth0, eth1
RESET is un-pushed
Hit any key to stop autoboot: 0
part0: Copying image to memory ... done.
part0: Checking sha1 (from 0x80060000 length 975288) ... match
part0: sha1 calculated: 38605dbee3ae20722f7baf28704cf9f821beda6a
## Starting application at 0x80060000 ...
starting stage2
decompressing embedded kernel image 0x81c024f0(0xebcaa)
got osize 2b7134

Does the rx pin of your router work at all (interrupting or not, your key presses should be reported on the screen, maybe in u-boot or later on in the vendor firmware)?

If not, check your cables again (and the connectivity between tx of your ftdi and the rx pin of your router), quite a few vendors intentionally disconnect rx (missing rx resistors, rx pulled down to GND, etc. pp.). A visual inspection of the PCB might help answering that question.

It is very likely that some parameter in the nvram is responsible for the waiting period.

1 Like

I believe the key press time is set to 0, and I'm looking for a way to increase it. Thank you for your time.

I need some way to change that parameter. Thank you for your time.

Would it be possible to reprogram the NAND of a Meraki MR16 to modify the boot using an FTDI FT232RL?

No, it's a serial adapter, not accessing the NAND directly.