[tprrt]

The ROM code of the TH1520 exposes a Fastboot interface in USB download mode (2345:7654). Download the image holding SPL, OpenSBI and U-Boot to the "ram" pseudo-partition and start it with "reboot". SPL initializes the DRAM, so no other boot stage is needed.

Tested on a BeagleV-Ahead with the vendor U-Boot SPL.

snagrecover -s th1520 -f th1520-beaglev-ahead.yaml --loglevel debug
2026-10-15 15:51:37,510 [DEBUG] Searching for USB device paths matching 2345:7654...
2026-10-15 15:51:37,534 [DEBUG] recovery_config:{'soc_model': 'th1520', 'soc_family': 'th1520', 'usb_path': (9, (2, 3, 2, 5, 3)), 'firmware': {'u-boot': {'path': '/home/tperrot/Downloads/ahead-yocto-1.1.2-20230610/u-boot-with-spl.bin'}}, 'args': {'soc': 'th1520', 'firmware_file': ['th1520-beaglev-ahead.yaml'], 'firmware': None, 'uart': None, 'baudrate': 115200, 'netns': 'snagbootnet', 'loglevel': 'debug', 'logfile': 'board_recovery.log', 'rom_usb': None, 'usb_path': None, 'list_socs': False, 'version': False, 'template': None, 'udev': False, 'am335x_setup': False}}
2026-10-15 15:51:37,534 [INFO] Starting recovery of th1520 board
2026-10-15 15:51:37,538 [INFO] Installing firmware u-boot
2026-10-15 15:51:37,538 [INFO] Downloading file...
2026-10-15 15:51:37,541 [DEBUG] fastboot DATA length: 963760
2026-10-15 15:51:37,790 [INFO] fastboot OKAY
2026-10-15 15:51:37,791 [DEBUG] fastboot OKAY
2026-10-15 15:51:37,791 [INFO] Done
2026-10-15 15:51:37,792 [INFO] Starting firmware...
2026-10-15 15:51:37,793 [DEBUG] fastboot OKAY
2026-10-15 15:51:37,793 [INFO] Done
2026-10-15 15:51:37,793 [INFO] Done installing firmware u-boot
2026-10-15 15:51:37,794 [INFO] Done recovering th1520 board
2026-10-15 15:51:37,794 [INFO] Logs were appended to board_recovery.log

picocom /dev/ttyUSB0
brom_ver 7
[APP][E] protocol_connect failed, exit.
Starting download of 963760 bytes

downloading of 963760 bytes finished

U-Boot SPL 2020.01 (Jun 10 2023 - 20:19:32 +0000)
FM[1] lpddr4x singlerank freq=3733 64bit dbi_off=n sdram init
ddr initialized, jump to uboot
image has no header


U-Boot 2020.01 (Jun 10 2023 - 20:19:32 +0000)

CPU:   rv64imafdcvsu
Model: T-HEAD c910 light
DRAM:  4 GiB
C910 CPU FREQ: 750MHz
AHB2_CPUSYS_HCLK FREQ: 250MHz
AHB3_CPUSYS_PCLK FREQ: 125MHz
PERISYS_AHB_HCLK FREQ: 250MHz
PERISYS_APB_PCLK FREQ: 62MHz
GMAC PLL POSTDIV FREQ: 1000MHZ
DPU0 PLL POSTDIV FREQ: 1188MHZ
DPU1 PLL POSTDIV FREQ: 1188MHZ
MMC:   sdhci@ffe7080000: 0, sd@ffe7090000: 1
Loading Environment from MMC... OK
Error reading output register
Warning: cannot get lcd-en GPIO
LCD panel cannot be found : -121
splash screen startup cost 15 ms
In:    serial
Out:   serial
Err:   serial
## Resetting to default environment
env ethaddr not exist or invalid
env eth1addr not exist or invalid
Saving Environment to MMC... Writing to MMC(0)... OK
Writing GPT: success!
dwc3_gadget_start maximum_speed:5 revision:0x5533330b
dwc3_gadget_start DWC3_DCFG:0x80804
dwc3_gadget_conndone_interrupt speed:0 dwc3_dsts:0x20000
dwc3_gadget_conndone_interrupt speed:0 dwc3_dsts:0x3ec68
Net:
Warning: ethernet@ffe7070000 (eth0) using random MAC address - 2e:03:45:04:99:06
eth0: ethernet@ffe7070000ethernet@ffe7070000:0 is connected to ethernet@ffe7070000.  Reconnecting to ethernet@ffe7060000

Warning: ethernet@ffe7060000 (eth1) using random MAC address - d6:fe:c4:4d:ff:03
, eth1: ethernet@ffe7060000
Hit any key to stop autoboot:  0
C910 Light#
C910 Light#

[jacmet]

Do you mean "not known to" or "known to not"?