topic Re: SD/MMC Boot using BCB in iMX233 in i.MX Processors

SD/MMC Boot using BCB in iMX233

OtavioSalvador — Fri, 25 Jan 2013 19:42:21 GMT

We've been working at adding support for i.MX233 in mainline U-Boot without using imx-bootlets. So far we have a great success adding basic support for it.

Currently I've been working at mxsboot tool to generate a binary blob capable of being directly put into SD/MMC and work.

In i.MX28 we use MBR and put a Boot Control Block (BCB) Data Structure in the first block of firmware partition however this does not seem to work. Checking i.MX23 datasheet it does not say anything about it support or not the BCB header.

Could someone confirm to me if BCB header is supported in MBR for i.MX23?

Re: SD/MMC Boot using BCB in iMX233

jimmychan — Wed, 30 Jan 2013 07:02:46 GMT

According to the i.MX23 Reference Manual,

The SD/MMC boot mode requires either a Boot Control Block (BCB) or Master Boot Record (MBR) on

the device. The boot loader will first search for a MBR. If found, it will use the MBR data to find the boot

image. If the MBR is not present, the boot loader will search for a BCB. If found, the BCB will provide

the boot image located and size to the boot loader. If neither structure is fount, the boot loader will return

an error to the ROM.

Re: SD/MMC Boot using BCB in iMX233

OtavioSalvador — Wed, 30 Jan 2013 10:17:53 GMT

Hello jimmychan,

I read this in the manual and also I did compare it to the iMX28 manual. My concern is if we can embed the BCB after MBR (in the partition tagged with '0x50') so it works as iMX28 does?

Currently I've been using a 4 sector offset since the tagged partition to the boot to work but I'd like to not need the offset and use a proper header setup to inform it to the BootROM.

Can you check it for me?