On Tue, Aug 11, 2020 at 12:35 PM Pablo Rath pablo@parobalth.org wrote:
On Tue, Aug 11, 2020 at 11:37:41AM +0100, Luke Kenneth Casson Leighton wrote:
Ok. I have tried that now. Pressed "2" while applying power over USB-OTG but an Allwinner USB FEL device is not found with 'sunxi-fel version'. Also tried to boot with my known working µSD-Card but there is no output on UART.
hm ok there is one more "trick" - actually uploading (and executing) the spl bootloader followed by u-boot and everything else https://linux-sunxi.org/FEL/USBBoot#Boot_the_system_over_USB
the old version, fel-boot, you had to first "run" then "execute". the newer version (sunxi-fel) looks like it does run-and-execute.
the first binary (the spl bootloader) fits into the 16k SRAM and until that's executed (and it initialises the PLL and DDR3) there's flat-out no chance of uploading anything at all into the upper areas of memory (0x42000000) which are in the DDR3 RAM area.
i have in the past set up a linux kernel to convert the USB-OTG into a usbserial "gadget", and also a usbnet-compatible g_ether "gadget". the first way was successful in showing early console logs, and the second was enough to get a USB eth0 that i could ssh in over.
l.