U-boot has had support for years, but it is enabled by default only
for some boards/targets.

After I flashed my NanoPi R6S's eMMC (no SD-card) as per INSTALL.arm64:

	=> setenv serverip6 fe80::1
	=> tftpboot BOOTAA64.EFI -ipv6
	ROUTER SOLICITATION 1
	Set gatewayip6: fe80:0000:0000:0000:fce1:baff:fed0:2e5c, prefix_length: 64
	Using ethernet@fe1c0000 device
	TFTP from server fe80:0000:0000:0000:0000:0000:0000:0001; our IP address is fe80:0000:0000:0000:5c27:b1ff:fe14:a9c9
	Filename 'BOOTAA64.EFI'.
	Load address: 0xc00800
	Loading: ################
	         1.7 MiB/s
	done
	Bytes transferred = 229585 (380d1 hex)
	=> bootefi $loadaddr
	Booting /BOOTAA64.EFI
	disks: sd0
	>> OpenBSD/arm64 BOOTAA64 1.22
	boot> 

iPXE also boots this way, but then hangs, at least on the serial:

	Booting /ipxe.efi
	iPXE initialising devices...


	iPXE 1.21.1+ (ge9a2) -- Open Source Network Boot Firmware -- https://ipxe.org
	Features: DNS HTTP iSCSI TFTP VLAN SRP AoE EFI Menu

	Press Ctrl-B for the iPXE command line...

I'll investigate that next, but IPv6 itself works fine incl. the
ping6 and pxe commands.

I don't use DHCPv6 and omitting it causes interactive prompts,
hence why it's disabled.

Image size growth seems negligible:

	$  du -k u-*
	9408	u-boot-rockchip.bin
	9424	u-boot-rockchip.bin.new

Feedback? OK?


Index: Makefile
===================================================================
RCS file: /cvs/ports/sysutils/u-boot/rk3588/Makefile,v
diff -u -p -r1.10 Makefile
--- Makefile	9 Aug 2025 09:53:19 -0000	1.10
+++ Makefile	30 Nov 2025 20:23:33 -0000
@@ -1,4 +1,5 @@
 VERSION=	2025.07
+REVISION=	0
 
 SOC=		rk3588
 
@@ -27,6 +28,11 @@ EXTRACT_ONLY=	${DISTNAME}${EXTRACT_SUFX}
 
 MAKE_ENV+=	BL31=${FULLDISTDIR}/${RK3588_BL31}
 
+ENABLE_OPTS=	IPV6 \
+		IPV6_ROUTER_DISCOVERY \
+		CMD_PING6
+DISABLE_OPTS=	CMD_DHCP6
+
 pre-build:
 	cc -o ${WRKSRC}/rkbinpatch ${FILESDIR}/rkbinpatch.c 
 	cd ${WRKSRC} && \
@@ -41,7 +47,9 @@ do-build:
 	        O="build/${BOARD}" \
 	        -f ${MAKE_FILE} "${BOARD}"_defconfig
 	cd ${WRKSRC}/build/${BOARD} && \
-	    ../../scripts/config --set-val BAUDRATE 115200
+	    ../../scripts/config --set-val BAUDRATE 115200 \
+	        ${ENABLE_OPTS:=-e %} \
+	        ${DISABLE_OPTS:=-d %}
 	cd ${WRKSRC} && \
 	    ${SETENV} ${MAKE_ENV} ROCKCHIP_TPL=${RK3588_TPL} ${MAKE_PROGRAM} \
 	        ${MAKE_FLAGS} O="build/${BOARD}" \