Hi Peter, On Sun, 5 Jul 2020 at 05:33, Peter Geis <pgwipeout@xxxxxxxxx> wrote: > > 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? Yes, so long as you know the address. Is the MMU turned off? Cache? > > > > > 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. OK. Maybe there is someone on this list with a bit more Android booting experienec? > > 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 OK, I'm sure it is possible. Do you have the source code for the fastboot code that boots U-Boot? Regards, Simon
