diff --git a/README.md b/README.md
index 2a07a22..b1e9cee 100644
--- a/README.md
+++ b/README.md
@@ -133,9 +133,13 @@ Confirmed on hardware, from a USB stick:
 - The framebuffer console works (`simple-framebuffer`, 240x67)
 - The root filesystem mounts, systemd starts, and it reaches a login prompt
 - Networking works over a USB WiFi dongle, and sshd is reachable
-- `build/install-to-disk.sh` copies it onto the internal UFS
+- `build/install-to-disk.sh` copies it onto the internal UFS, and it boots from
+  there with the stick removed — 18s to multi-user, no failed units
 
-Not yet confirmed: booting from the internal drive rather than USB.
+The RTC cannot be set on this machine and reads 1970 at every boot, so `chrony`
+is installed and corrects the clock once the network is up. Until it does, rpm
+rejects package signatures dated after the (wrong) current time and reports
+installed packages as missing — see [docs/install.md](docs/install.md).
 
 Onboard WiFi does not appear at all, and audio, sensors, video decode and
 accelerated graphics are all absent — every one of them waiting on the
diff --git a/docs/install.md b/docs/install.md
index a6d21b1..726a789 100644
--- a/docs/install.md
+++ b/docs/install.md
@@ -85,6 +85,45 @@ and a root partition; `mkfs.vfat` and `mkfs.ext4 -O
 `/etc/kernel/cmdline`, `root=UUID=` in `/boot/loader/entries/*.conf`, and the
 `--fs-uuid` in both `/boot/grub2/grub.cfg` and `EFI/fedora/grub.cfg`.
 
+## The clock, and why dnf lies about missing packages
+
+This machine's RTC cannot be set — `hwclock --systohc` fails with
+`ioctl(RTC_SET_TIME) to /dev/rtc0 to set the time failed: No such device` — and
+it reads 1970 at every boot. systemd compensates by advancing the clock to its
+own build date, which is close enough to look right and wrong enough to break
+rpm.
+
+The symptom is baffling if you have not seen it before:
+
+```
+$ sudo dnf install net-tools
+Transaction failed: Rpm transaction failed.
+  - systemd is needed by net-tools-2.0-0.77.20160912git.fc44.aarch64
+```
+
+systemd is plainly installed — the machine booted. But with the clock behind
+the package's signing date, rpm rejects the signature as *not yet valid*, skips
+that header entirely, and concludes the package is absent:
+
+```
+Signature 85b4 created at Sat Jul 25 18:33:30 2026 invalid: signature is not alive
+  because: Not live until 2026-07-25T18:28:30Z
+error: rpmdbNextIterator: skipping h#     282
+package systemd is not installed
+```
+
+`chrony` is installed and enabled, and fixes this within a few seconds of the
+network coming up — check with `timedatectl`. The gap only matters if you run
+`dnf` before that, or on a machine with no network yet. Set it by hand in that
+case:
+
+```sh
+sudo date -u -s "2026-07-27 16:33:00"
+```
+
+Any roughly-correct time will do; it only has to be later than the packages
+were signed.
+
 ## If it does not boot
 
 The kernel command line is the first thing to change. It lives in
@@ -98,6 +137,7 @@ one boot by pressing **e**.
 | USB dies during boot | Add `modprobe.blacklist=qcom_q6v5_pas` |
 | Cannot find root filesystem | The initramfs is missing the UFS drivers — see `overlay/etc/dracut.conf.d/10-c630.conf` |
 | 90-second stall early in boot | Add `systemd.tpm2_wait=0` |
+| `dnf` says a package that is obviously installed is missing | The clock is behind — see above |
 
 Adding `earlycon` and `ignore_loglevel` will tell you a great deal more about
 which of these it is.