I didn't just place code at 2000h. It wouldn't work. I had also to modify U-Boot SPL to make it load U-Boot Proper from specific address:
CONFIG_SYS_NAND_U_BOOT_OFFS=0x802000 CONFIG_SYS_NAND_U_BOOT_OFFS_REDUND=0x802000 These lines in .config are crucial (as rebuilding U-Boot SPL with them). On Tuesday, 5 April 2022 at 00:21:44 UTC+3 ku...@szczodrzynski.pl wrote: > > I can confirm that this works (the method for running SPL as Boot0). > > I've researched this a bit further and I know the reason for why that > modification helps. When flashing with LiveSuit, the updater binaries > (update_boot0.axf and update_boot1.axf) first grab the images to RAM, then > parse their headers, check the checksum. Then, a part of the header called > "storage data" is populated with data received from some other part of the > updating process (possibly another .axf file, maybe related to > configuration of the sys_config.fex). Boot0 and Boot1 have that part at > 0x1C8 and 0x81D0 offset, respectively. Considering that U-Boot SPL doesn't > have the entire eGON header and it starts at 0x60, the updater is > overwriting part of SPL code - thus resulting in a corrupted firmware. As > for U-Boot as Boot1, it overwrites code at 0x81D0. You have placed the code > at 0x2000, so my guess is that you still have some part in the firmware > overwritten. Maybe it just works by accident. > > Anyways, I'm currently working on a binary-patched updater image, that > will allow to flash Boot1 without any 0-byte padding, straight from U-Boot > mainline. It won't even need an eGON header and will ignore the checksum. > After that, I'll probably also patch the Boot0 updater not to overwrite > anything, making it possible to just grab the SPL and flash it. > > poniedziałek, 4 kwietnia 2022 o 11:42:07 UTC+2 Daft Soft napisał(a): > >> Hi, all! >> So, I have the complete solution to make A20 boot from NAND (SPL, U-Boot) >> + >> SATA (DTB, Kernel, RootFS). This is to exclude SD-Card from boot process. >> >> First part is a20_nand branch from U-Boot from >> https://gitlab.com/m.motyl83/u-boot.git <http://U-Boot> >> >> NB! >> a20_nand branch is crucial >> >> This will make appropriate SPL (spl/sunxi-spl.bin), which can be loaded >> to >> NAND via FEX and will boot. >> >> At this moment we have one problem: we have no U-Boot proper prepared for >> flashing via FEX (u-boot-dtb.bin will be rejected as file with wrong >> signature). >> U-Boot does not build U-Boot proper with SUNXI eGON.BT1 signature at all. >> >> So I've modified original mksunxi hosttool from U-Boot (source file >> included). >> It places correct signature to header of image followed by U-Boot proper >> code. >> >> eGON.BT signatures start from ARM "B" instruction (4 bytes - instruction >> opcode >> and address to branch to). >> Original mksunxi calculates this "branch" instruction (address) to jump >> over >> eGON header. For Boot0 it works perfectly (because it is standard offset >> which >> is used in any Boot0 image by BROM - be it proprietary Boot0 or U-Boot >> SPL). >> But not for Boot1... >> >> I don't know where IP (instruction pointer) points to when SPL loads >> U-Boot >> proper and tries to "jump" (speaking in terms of x86) to it. So, I didn't >> know how to calculate address of this instruction. >> But we know that U-Boot proper code works when SPL jumps right to it >> (this is proved by inspecting u-boot-sunxi-with-spl.bin and playing with >> loading images via USB-FEL). >> >> Thus I've modified generation of Boot1 image - it places U-Boot proper >> code with some constant offset (2000h, filled with zeroes). >> (Also we need to make more space in SUN4I_SRAM_SIZE, because it is Boot1 >> - >> it is larger than Boot0). >> >> Next step is to modify config. We need to tell SPL to load U-Boot proper >> from specific offset (avoiding BROM signature and "B" instruction - it >> will >> not read it from NAND at all). >> This lines are: >> >> CONFIG_SYS_NAND_U_BOOT_OFFS=0x802000 >> CONFIG_SYS_NAND_U_BOOT_OFFS_REDUND=0x802000 >> >> (These lines are for SPL, so you need to rebuild it to work with U-Boot >> proper >> which is generated by modified mksunxi). >> >> After all this we can use modified mksunxi (I call it mksunxi-bt1) to >> build >> Boot1 image which contains signature, correctly placed U-Boot proper >> code, >> can be flashed via FEX and started by SPL (with modified "U-Boot Offs"). >> > -- You received this message because you are subscribed to the Google Groups "linux-sunxi" group. To unsubscribe from this group and stop receiving emails from it, send an email to linux-sunxi+unsubscr...@googlegroups.com. To view this discussion on the web, visit https://groups.google.com/d/msgid/linux-sunxi/44fe1465-7d30-4b45-bbe2-a4a2b36526dbn%40googlegroups.com.
