Agilex7 u-boot: how to stop and prompt?

I just built a u-boot for Agilex7 and it seem to work:

U-Boot SPL 2023.01-26427-gd77556ee14 (Oct 25 2024 - 13:02:53 +0200)
Reset state: Cold
MPU          1200000 kHz
L4 Main       400000 kHz
L4 sys free   100000 kHz
L4 MP         200000 kHz
L4 SP         100000 kHz
SDMMC          50000 kHz
DDR: 8192 MiB
SDRAM-ECC: Initialized success with 1742 ms
QSPI: Reference clock at 500000 kHz
WDT:   Started watchdog@ffd00200 with servicing every 1000ms (10s timeout)
Trying to boot from MMC1
Card did not respond to voltage select! : -110
spl: mmc init failed with error: -95
Trying to boot from SPI

But how can I make it stop at the u-boot prompt, either always or whenever I hit a key within a given time?

It appears that CONFIG_BOOTDELAY is set to 5.

$ grep -i bootdelay configs/socfpga_agilex_defconfig
CONFIG_BOOTDELAY=5

I would like to stop at the u-boot prompt and run commands manually.

Rather than trying to boot automatically from MMC I would like it to halt so I can manually enter commands or run a script.