On Sat, Jul 4, 2020 at 3:53 PM Simon Glass <sjg@xxxxxxxxxxxx> wrote: > > Hi Peter, > > On Fri, 3 Jul 2020 at 06:33, Peter Geis <pgwipeout@xxxxxxxxx> wrote: > > > > Good Morning, > > > > I am attempting to expand on the work for chainloading U-Boot on the > > nyan-big in order to chainload U-Boot on the Ouya Tegra30 device from fastboot. > > I have so far been unsuccessful at getting any output from U-Boot > > through this method. > > > > I'm building the cardhu board with tweaks for Ouya's specifications > > similar to my work for the linux kernel. > > I build the image using mkbootimg --kernel u-boot.bin --ramdisk > > /dev/null --output u-boot-android.bin. > > I then fastboot boot u-boot-android.bin. > > > > I've tried tweaking the text base and tried both standard debug and > > low level debug. > > > > Do you think you could give me some insight into where I'm going wrong? > > Is it possible that fastboot expects a relocatable image? If you set > up the debug UART very early you might be able to output a character > in start.S ? Yes, fastboot expects a relocatable image. As I understand it though, if I get the text base correct, U-boot will not need to relocate. The debug UART is already set up when it fastboot jumps to the loaded kernel, So I should be able to dump data to the expected raw address and it will show up? > > BTW does U-Boot have support for the fastboot protocol? Perhaps you > could just use U-Boot? The Ouya is locked with a signed boot loader, like most consumer android devices. Unlike most other devices, it does not have a hardware method for entering the bootloader in case of a brick. We are currently using a hacked kernel that stores another kernel in "safe" ram via kexec and hard resets the board, but a proper bootloader would be much more preferable. I found one example of where fastboot chainloaded u-boot successfully on the galaxy nexus, from 2013. https://forum.xda-developers.com/galaxy-nexus/bootloader-boot-multi-boot-support-t2201146 > > Regards, > Simon
