Can't boot after update of the system (black screen)

[nmoul]

Hello,

Since I did an update today (pacman -Syu), my raspberry pi doesn't boot: after the raspberry boot screen, I just have a black screen without text (so no error message...).
My system is on a USB hard drive, but just to make sure I installed from the raspberry pi boot screen a new arch system on a SD card. The system works fine. But again after an update, I have a black screen when I reboot.

I did again a new installation, but this time I replaced the kernel and header packages (3.6.??) with the 'latest' version (linux-raspberrypi-latest 3.10.7-1), without updating the other packages. A reboot is successful.

But again after an update of the whole system (pacman -Syu), I have a black screen on reboot.

If it can help there was some raspberry firmware and bootloader related packages amount the update.

Thanks

[nmoul]

I reply to myself: It seems that the problem is related to the firmware and/or the raspberrypi-firmware-bootloader
packages. Indeed I got an old version from my hard drive and replace the content in /boot.
Now the system restart normally.

But I have now another problem: I can't boot using my hard drive like before.
Booting on the SD card my hard drive is not seen by the system: no /dev/sdaX, no reaction in dmesg when I plug the USB drive. Weird. The drive works perfectly from a PC (under Arch by the way).

[sdjf]

You don't say what kind of USB drive, if it is a hard drive, and you have not plugged it in to a powered hub, I would not be at all surprised if it was not recognized. Inadeauate power can cause serious problems with mounting devices.

And sometimes my Pi gets into a snit, totally disconnecting all USB. I find disconnecting the hub and reconnecting it will often get all devices to be properly recognized again.

[nmoul]

Sorry for the late reply.

I didn't precise the kind of drive because it was previously booting fine before an arch update. It's a mini hard drive, plugged on an alimented USB hub. Nothing changed except arch packages. And the hard drive still works without a glitch when plugged on a PC.
It may be my arduino that have a hardware pb. But as my first problem was clearly due to a package update, I would not be surprised for the second problem to have the same origin.

Well I didn't had time to investigate further.