BeagleBone Green Wireless - serial debug port hangs after sending u-boot-spl.bin (since v2021.01)

[Darren Ng]

(Hello, from a U-Boot NOOB.)

Issue
-----
After sending u-boot-spl.bin with xmodem, the serial debug port seems to
hang.
Neither "...U-Boot SPL...\n...\nTrying to boot from UART..."
nor "CCC..." shows up in minicom.
Always 0% if I try sending u-boot.img with xmodem anyway.

Target Device
-------------
Seeed Studio BeagleBone® Green Wireless
https://seeeddoc.github.io/Beaglebone_green_wireless/
https://wiki.seeedstudio.com/BeagleBone_Green_Wireless/#hardware-overview
https://source.denx.de/u-boot/u-boot/-/commits/master/configs/am335x_boneblack_vboot_defconfig

Matrix
------
This issue applies to tags ever since v2021.01. In the following table:
(x) - This issue applies.
(O) - I can send both u-boot-spl.bin and u-boot.img
      then execute u-boot commands without trouble.
------
tag          result
------------ ------------------
v2021.07-rc1 (x) hangs
v2021.04     (x) hangs
v2021.01     (x) hangs
v2020.10     (O) success
v2020.07     (?) not tested yet
v2020.04     (?) not tested yet
v2020.01     (O) success


Toolchain
---------
"Official toolchain for Arch ARM builds via distcc on x86_64 volunteers"
https://aur.archlinux.org/packages/distccd-alarm-armv7h
https://archlinuxarm.org/wiki/Distcc_Cross-Compiling
---------
$ gcc --version
gcc (GCC) 10.2.0
Copyright...
---------
$ cd /opt/x-tools7h/arm-unknown-linux-gnueabihf/bin/
$ ./armv7l-unknown-linux-gnueabihf-gcc --version
armv7l-unknown-linux-gnueabihf-gcc (crosstool-NG 1.23.0.418-d590) 10.2.0
Copyright...


Build
-----
tar xf ...
cd u-boot-*/
export PATH="$PATH:/opt/x-tools7h/arm-unknown-linux-gnueabihf/bin/"
export CROSS_COMPILE="armv7l-unknown-linux-gnueabihf-"
export KBUILD_OUTPUT="O"
make -j4 am335x_boneblack_vboot_defconfig
make -j4 all


Regards,
Darren "Un1Gfn" Ng
Jumat, 7 Mei 2021 WITA(UTC+8)