upgrade RPi3 (armv7) running 13.2 to 13.3

Hello,

I’m running FreeBSD v13.2 on a RPi3 (armv7):

```
[root@aeschylus ~]# freebsd-version
13.2-RELEASE
[root@aeschylus ~]# getconf LONG_BIT
32
[root@aeschylus ~]# dmesg|grep -i cpu
CPU: ARM Cortex-A7 r0p5 (ECO: 0x00000000)
CPU Features:
FreeBSD/SMP: Multiprocessor System Detected: 4 CPUs
cpulist0: <Open Firmware CPU Group> on ofwbus0
cpu0: <Open Firmware CPU> on cpulist0
bcm2835_cpufreq0: <CPU Frequency Control> on cpu0
cpu1: <Open Firmware CPU> on cpulist0
cpu2: <Open Firmware CPU> on cpulist0
cpu3: <Open Firmware CPU> on cpulist0
bcm2835_cpufreq0: ARM 600MHz, Core 250MHz, SDRAM 400MHz, Turbo OFF
```

Armv7 is not tier1 and apparently it’s not supported anymore. Here’s the fetch output:

```
[root@aeschylus ~]# freebsd-update fetch
Looking up update.FreeBSD.org mirrors... 3 mirrors found.
Fetching public key from update2.freebsd.org... failed.
Fetching public key from update1.freebsd.org... failed.
Fetching public key from dualstack.aws.update.freebsd.org... failed.
No mirrors remaining, giving up.

This may be because upgrading from this platform (arm)
or release (13.2-RELEASE) is unsupported by freebsd-update. Only
platforms with Tier 1 support can be upgraded by freebsd-update.
See https://www.freebsd.org/platforms/ for more info.

If unsupported, FreeBSD must be upgraded by source.
```

Strangely, I can download and upgrade packages using “pkg”. What is the optimal way to an upgrade path in this platform?
Is there any other mirror I safely run `freebsd-update  fetch` against, for this platform?

Kind regards,

--
Panagiotis (atmosx) Atmatzidis
GPG:       gpg --keyserver pgp.mit.edu --recv-keys 1A7BFEC5