I want to build custom image for BPI-R64, probably with upstream U-Boot (I see that upstream has
mt7622_rfb_defconfig (64-bit?)) and definitelly with upstream Linux, however I can’t find good description of how MediaTek MT7622 boots from sd card, so I have several question, mostly about U-Boot, because I cant even load U-Boot now)
- Does MT7623N from BPI-R2 have the same boot sequence as MT7622 from BPI-R64?
- Whether upstream U-Boot with config
mt7622_rfb_defconfigcould load upstream kernel for BPI-R64? Is it 32bit or 64bit U-Boot config? What is the difference between
- What is the easiest way to load upstream U-Boot from SD card in 64 bit mode?
- What happens when BPI-R64 powers up with SW1 in position 1? According to official BSP It tries to load first stage loader starting from 2048 byte on SD card (in case of official BSP it is some prebuild binary
preloader_bpi-r64_forsdcard-2k.img), which will load ATF (also prebuild
BPI-R64-atf.img, and it is secret for me what id does), which, in turn, load U-Boot built from u-boot-mt, and this U-Boot loads Kernel. However, alternative way to load is to use modified upstream ATF from https://github.com/frank-w/BPI-R64-ATF repo, and in this case it seems mt7622 load first stage loader from offset 0x80000 or 524288 byte. That’s really strange.
- Does upstream kernel works fine with mt7622?