Raspberry Pi 4 Model B Revision 1.5 and U-Boot >= 2025.07 stalls issue.

[Matteo GUGLIELMI]

TFTP downloads in U-Boot >= 2025.07 on Raspberry Pi 4 Model B Revision 1.5
stall during transfer (continuous T output), while the same setup works
correctly with U-Boot 2025.04.

Please note that U-Boot starts correctly, DHCP works, and small TFTP still
works, but large TFTP stalls (e.g., kernel or initramfs files).

On the contrary, Raspberry Pi 4 Model B Revision 1.4 does not have the
stall issue and can download files correctly up to the latest stable
version of U-Boot (2026.04).

Thank you.