I re-built a version of u-boot as 2018-07 release (BBBlf) for booting up from micro USB.
U-Boot SPL 2018.07-dirty
I re-built the latest version of u-boot as 2020-07 release.
Here is what I did:
Erased EEPROM of BBBw (dev board)
loaded 2018-07 u-boot through micro USB
re-programmed EEPROM as orignal ( except serial number)
re-flashed debian (2020-10 buster version)
re-flashed U-Boot 2020.07-00442-g186529953f
I expected to successfully reboot to debian.
But when the u-boot is started, it still trying bootp and tftp as the version that loaded through micro USB. (Note: this is normal reboot without BOOT sw2 pressed). Here is the messages:
U-Boot SPL 2020.07-00442-g186529953f (Jul 22 2020 - 09:59:50 -0400) Trying to boot from MMC2 U-Boot 2020.07-00442-g186529953f (Jul 22 2020 - 09:59:50 -0400) CPU : AM335X-GP rev 2.1 Model: TI AM335x BeagleBone Black DRAM: 512 MiB WDT: Started with servicing (60s timeout) NAND: 0 MiB MMC: OMAP SD/MMC: 0, OMAP SD/MMC: 1 Loading Environment from FAT... <ethaddr> not set. Validating first E-fuse MAC Net: Could not get PHY for ethernet@4a100000: addr 0 eth2: ethernet@4a100000, eth3: usb_ether Hit any key to stop autoboot: 0 switch to partitions #0, OK mmc1(part 0) is current device Scanning mmc 1:1... switch to partitions #0, OK mmc1(part 0) is current device SD/MMC found on device 1 ** Invalid partition 2 ** ## Error: "bootcmd_nand0" not defined starting USB... Bus usb@47401800: Port not available. using musb-hdrc, OUT ep1out IN ep1in STATUS ep2in MAC de:ad:be:ef:00:01 HOST MAC de:ad:be:ef:00:00 RNDIS ready musb-hdrc: peripheral reset irq lost! high speed config #2: 2 mA, Ethernet Gadget, using RNDIS USB RNDIS network up! BOOTP broadcast 1 BOOTP broadcast 2 BOOTP broadcast 3
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It seems to me that the uboot environment settings was changed by u-boot of micro usb (2018 ver). So even the 2020 version is flashed, the environment is set to bootp and tftp.