Recently, i sucessfully install OpenWRT on 2 Meraki MR42 devices, using UART method.
At the end of install, it shows version :
OpenWrt SNAPSHOT r23456-81f667513a / LuCI Master git-23.158.78004-23a246e
Before starting configuration, i wanted to install lastest supported version. So i download the following file on MR42 page, and send it via the Luci "system - Flash new firmware image" menu. I uncheck the "keep settings", as nothing was set. openwrt-22.03.5-ipq806x-generic-meraki_mr42-squashfs-sysupgrade.bin
Now i can't access my device anymore. Did a do something wrong ? Is it possible to recover it without opening again ?
If there's a documented recovery procedure, you should try that - and flash a factory image. Images contain no migration mechanisms for downgrades, only for upgrades. Wiping settings was the smart thing to do but it won't catch any changes that were done to the images themselves.
Then mount a tftp server on my computer, and press reset on the Meraki. I saw the file uploading, rooter booting (whiote led flash, then fixed). But still no ping on 192.168.1.1 nor dhcp request.
I'll open it this night and look at the serial monitor.
I've a second unit up and running, and i'm a little scared about updating. Can someone give me advices on how to do it safely ?
It seems the serial pins are there (at least going by an image floating around on the forums here, so better hook up serial to see what's going wrong exactly at boot.
Yes. The hash after the dash is the last git commit your image was built from. The revision number (r.....) is a number that counts the amount of commits since the start, and cannot be readily linked to the tree. The commit hash however, you can retrieve that through git.openwrt.org or the GitHub mirror.
BTW I've had instances where not setting the right subnet on the client - ie setting 192.168.1.100 e.g. but not specifying it's a /24 - would prevent me from connecting. Did you double check that?