update u-boot

Niklas Molin wrote:

 

I just wanted to check what the best way is to update for instance the u-boot?

Our plan is to use a SSD to boot from and run the linux on.

On the Sabre-Lite, the OTP fuses have been blown in such a way that you will always boot from SPI flash. There's a couple of dip switches that allow you to load u-boot over the usb-otg port from a PC, but it's unlikley you'd want to do that for anything other than recovering from a failed flash of the SPI device.

The boards come with u-boot installed in the SPI flash device and the typical way to update u-boot is with an SD card - you break into u-boot before booting the OS and then run a specific update command to copy a version of u-boot from the sd-card into SPI flash.

There are a couple of (tiny) bits of code that you can put into SPI flash that will redirect the boot to either the SD-card or uSD sockets.  I've not seen anything to allow direct booting from SSD/SATA although it may be possible in the same way as the re-direct to SD-card.

Without the ability to change the OTP boot bits in the SoC, what you'd normally do is to have u-Boot in SPI flash with a bootscript that will then load the OS from a device of your choosing.

Whan updating the image or the u-boot on the SSD, what is the best method (via a PC or via the Freescale processor).

u-boot is unlikely to be on the SSD, but assuming it were, why wouldn't you just copy a new version onto the SSD from within the booted OS ?

When developing for Linux on the Freescal, do I need to have a JTAG cable?

Unless you're doing low level stuff, i.e. before linux has booted, or bare metal programming, I don't see why.

What do you have to hit to go into u-boot on your  SD-Card? And what software do you have to load to it ahead of time?

not sure I understand, Sabre-Lite uses the same u-boot as other boards, generally it all works the same.  However, on Sabre-Lite u-boot is not on the SD card, it's an a small (2MB) spi flash rom. As such u-boot loads when there's no SD card present.