CN9132 - Booting using the UART

I got the CEx7 CN9132, but do not have access to the evaluation board due to shipping problems. To get started, I’m using an Express-BASE7 (Adlink) as a carrier, but have encountered some issues.

The board is configured to boot from SPI, but apparently the flash is empty. This is the output:
BootROM - 2.03
Starting CP-0 IOROM 1.07
Booting from SPI NOR flash 1 (0x32)
Error: no valid header till end of media
Error: Failed boot attempt 01. error = 0x041

BootROM - 2.03
Starting CP-0 IOROM 1.07
Booting from SPI NOR flash 1 (0x32)
Error: no valid header till end of media
Error: Failed boot attempt 02. error = 0x018

BootROM - 2.03
Starting CP-0 IOROM 1.07
Booting from SPI NOR flash 1 (0x32)
Error: no valid header till end of media
Error: Failed boot attempt 03. error = 0x018

BootROM - 2.03
Starting CP-0 IOROM 1.07
Booting from SPI NOR flash 1 (0x32)
Error: no valid header till end of media
Error: Failed boot attempt 04. error = 0x018

Trying Uart…

To boot using the UART, I’ve done the following:
Cloned the CN913x build repository (GitHub - SolidRun/cn913x_build) to get access to the tools to boot through UART.
Downloaded the u-boot image u-boot-cn9132-cex7-A-spi.bin from SolidRun Images
Ran the provided script (mrvl_uart.sh), but without success.

I’ve tried to change the timing of when to power on the board in relation to when the script is executed, but I assume the escape sequence is only important when it actually have an image in flash that it can boot.

This is the output I get:

Using device connected on serial port “/dev/ttyS0”
Loading flash image file “…/…/u-boot-cn9132-cex7-A-spi.bin”
Press the “Reset” button on the target board and the “Enter” key on the host keyboard simultaneously
Sending …/…/u-boot-cn9132-cex7-A-spi.bin, 13796 blocks: Give your local XMODEM receive command now.
Xmodem sectors/kbytes sent: 0/ 0kRetry 0: Timeout on sector ACK

It will terminate unsuccessfully after several timeouts. It seems there’s no successful communication going on, and in fact I get the same output if I run the script without powering on the board.

I’ve tested the UART connection to another ComEx board, and I can both receive and transmit data to that board.

Any suggestions on how to proceed is greatly appreciated.