From mboxrd@z Thu Jan 1 00:00:00 1970 From: Helmut Raiger Date: Wed, 12 Feb 2014 10:56:30 +0100 Subject: [U-Boot] Chain loading an u-boot from an u-boot In-Reply-To: <52F9EF7A.5080805@denx.de> References: <52F8B3F5.8050101@hale.at> <52F9EF7A.5080805@denx.de> Message-ID: <52FB454E.5090800@hale.at> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de Hi Stefano, > Hi Helmut, > > > I understand the first two points, but why do you store the kernel again > with 1bit HW-ECC ? The second U-Boot is able to check with 4bit BCH and > your NAND requires 4bit. This is mainly due to performance requirements. Using 4bit BCH increases overhead and makes DMA (currently not used in the kernel driver) a lot slower. We thought we might slip through with 1bit HW-ECC, but we will test this (hopefully not in the field this time ;-) ) > I agree with Andreas' analyses. It seems that the second u-boot > overwrites your running U-Boot and only if they are identical you have > no problem, that means that you are not changing the running code. I double-checked now, the running u-boot is not overwritten. When the 2nd u-boot relocates it overwrites the first one, but that shouldn't be a problem. The first u-boot keeps working after loading (but not running) the second one without issues. Only the 'go' crashes the system. u-boot starts stand-alone application fine, just as the kernel. I really can't see the point why another u-boot should be any different?! Helmut -- Scanned by MailScanner.