Hi.
We have several RB951Ui-2HnD upgraded from 6.42.12 to 7.1rc1

Routers works fine, but there is one BIG problem:

If you just reboot them, router becomes brick

It bootloops blinking 4 and 3 LED and no sound.

Tried to make reset or netinstall - not worked.

We have three bricked routers on this version of ROS.

Is there a way to fix them?

How did you get from 6.42 to 7.1rc?

IIRC routerboot has to be one of recent 6.xx to successfully boot any of v7. You might want to try netinstall one of bricked devices with 6.48, upgrade routerboot and only later go to 7.1rc2.

Maybe it's the problem I am having: The router reboots endless.
It helped to unplug the cables und re-insert after 20 seconds.

Problem is based on CAPsMAN. If CAPs connect very early and create interfaces, the router reboots.
As the problem still exists, my current fix is to disable CAPsMAN and re-enabling it 30 seconds after boot.

I "bricked" a cAP ac...seem similar issue...but no CAPsMAN involvement here. I wanted to use to test v7.1rc1 as an AP BUT netinstall doesn't seem to fix (tried both 7.1rc1 version & 6.48.4 version of netinstall matched with same ROS, on win10-64bit).

I think @mkx is has a point: I upgraded a "new" unit, but with the stock ROS/firmware, without going to latest stable. Now winbox, let me do that using System>Packages>Download&Install – I'd figured the restriction might have been lifted.

@zerolord, be curious to know if netinstall fixes your problem...

Anyway, I know I'm going to upgrade to a stable v6 before doing any future v7 upgrades – even if winbox allows it – an older v6 version may not know that "development" channel is a "bad idea" if your starting at older v6... if I recall my "in box" cAP ac came with pretty old firmware 6.44 (I think) – can't tell anymore since it's bricked.

@Amm0: I'm not talking about Router OS, which is upgraded via system->packages sub-menu, I'm talking about Routerboot firmware, which is upgraded via system->RouterBOARD submenu. The later can be compared to computer's BIOS (or UEFI) and if it's too old, it can't boot new OS kernel. Routerboot images come with RouterOS and can only be upgraded after new RouterOS is already running. Routerboot shipped with RouterOS around 6.47 and newer is required to boot ROS v7.

We'll see how stable release of v7 will handle these dependencies ...

@mkz -fair point that it's the older RouterBOOT that likely didn't like new v7.1rc1 ROS upgrade package... I didn't even get a chance to upgrade the firmware to v7.1 since it didn't come back after the ROS v7 package was on disk. So totally right the RouterBOOT remains older, until the firmware upgrade...

But after thinking about RouterBOOT... I tried using the "long term" netinstall (and associated "long term" ROS/firmware package). That worked to get to long-term installed and cAP working agin.

Since it recovered, while the cAP ac is maybe 6 month old TO ME, it had v6.43.10 firmware from the box. So guessing that big jump in version is what caused an issue going direct to v7.1...

I used to be careful at always getting to "stable" (ROS AND firmware) before doing anything v7.x – I was just feeling adventurous (since it is a test device) – but I think that's still a good idea to upgrade to "stable" in future.

As I said I don't CAPsMAN was involved, but maybe now that I think about it. If you press the reset button for the wrong amount of time, it would go in CAPS mode (soild light after blinking, ~10-15 seconds). For netintall, I normally just keep pressing the reset until it shows up in netinstall, but it's possible I "let up on the trigger" too... In which case, it COULD have been in CAPS mode, but since it didn't boot, I wouldn't have known

If "long term" netinstall doesn't fix it, I do recall trying at somepoint doing a "reset to defaults" (e.g. 5-10 second press) before trying the "long press" to PXE/netinstall – so maybe that how I got my cAP working. Hard to know for sure.