Update docs for FydeOS install on eMMC, stale Flex UEFI entry removed

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

CHROMEOS-FLEX.md

@@ -1,11 +1,14 @@
-# ChromeOS Flex on hp-chell's internal eMMC
+# ChromeOS (Flex / FydeOS) on hp-chell's internal eMMC
+
+**Currently installed: FydeOS** (`iris` build, 2026-09-27). It replaced
+ChromeOS Flex; `install-flex-emmc.sh` handles both images.
 
 hp-chell (HP Chromebook 13 G1, MrChromebox UEFI firmware) dual-boots:
 
 | OS | Disk | Notes |
 |---|---|---|
 | KDE neon | `sda`, external USB/SD card (117GB) | primary OS, owns GRUB |
-| ChromeOS Flex | `mmcblk0`, internal eMMC (29GB) | installed from neon, see below |
+| FydeOS (was ChromeOS Flex) | `mmcblk0`, internal eMMC (29GB) | installed from neon, see below |
 
 Because neon lives entirely on external media, the eMMC can be wiped and
 reinstalled from the running neon system with no risk to neon.
@@ -29,7 +32,11 @@ sudo ./install-flex-emmc.sh ~/Downloads/chromeos_<ver>_reven_recovery_stable-cha
 - Updates the GRUB chainload entry (below) with the new EFI partition's
   UUID and runs `update-grub`.
 
-Last installed: 2026-09-27, Flex `16640.57.0` (stable, `reven`).
+Install history on the eMMC:
+- 2026-09-27: ChromeOS Flex `16640.57.0` (stable, `reven`). It
+  auto-updated to `16640.61.0` on first boot.
+- 2026-09-27: **FydeOS** `FydeOS_for_PC_iris_v23.0-SP1-io.bin`
+  (`amd64-fydeos_iris-io`, `16700.56.23.51`), which replaced Flex.
 
 ## Why not just `dd` the image
 
@@ -111,7 +118,25 @@ Each of these broke an attempt during the 2026-09-27 install:
   The log must not be in `/tmp` if another user owns the file (root is
   denied by `fs.protected_regular`).
 
-## Resulting layout (2026-09-27)
+## Resulting layout
+
+FydeOS (current, 2026-09-27):
+
+```
+mmcblk0      29.1G
+├─mmcblk0p1  23.7G ext4   STATE
+├─mmcblk0p2    16M        KERN-A
+├─mmcblk0p3   2.7G ext4   ROOT-A
+├─mmcblk0p4    16M        KERN-B
+├─mmcblk0p5   2.7G ext4   ROOT-B
+├─mmcblk0p6-7 512B        KERN-C / ROOT-C
+├─mmcblk0p8    16M ext4   OEM
+├─mmcblk0p9-10 512B       reserved / reserved
+├─mmcblk0p11    8M        RWFW
+└─mmcblk0p12   32M vfat   EFI-SYSTEM (UUID F35E-F13C, PARTUUID 18151E4F-...)
+```
+
+ChromeOS Flex (2026-09-27, before FydeOS replaced it):
 
 ```
 mmcblk0      29.1G
@@ -126,24 +151,26 @@ mmcblk0      29.1G
 └─mmcblk0p12  256M vfat   EFI-SYSTEM (UUID CBE4-703E)
 ```
 
-The ESP is copied from the image, so its FAT UUID (`CBE4-703E`) survived
+The ESP is copied from the image, so its FAT UUID comes from the image:
-the reinstall unchanged. The install itself left the UEFI boot entries
+`CBE4-703E` for Flex (it survived the Flex reinstall unchanged) and
+`F35E-F13C` for FydeOS. The install itself left the UEFI boot entries
 and `BootOrder` untouched, but Flex's first auto-update changed them.
 See "Flex takes over the UEFI boot order on updates" below.
 
-## Booting Flex
+## Booting ChromeOS (FydeOS)
 
 Two ways:
 
 1. **From GRUB** (neon's menu, shown for 5s): the entry "ChromeOS Flex
-   (internal eMMC)" in `/etc/grub.d/40_custom` chainloads Flex's own EFI
+   (internal eMMC)" in `/etc/grub.d/40_custom` chainloads the eMMC ESP's
-   loader (`crdyboot`) from the eMMC's ESP:
+   own loader: FydeOS's GRUB now (Flex's was `crdyboot`). The title was
+   kept on purpose, since FydeOS is still ChromeOS.
    ```
    menuentry "ChromeOS Flex (internal eMMC)" {
        insmod part_gpt
        insmod fat
        insmod chain
-       search --no-floppy --fs-uuid --set=root CBE4-703E
+       search --no-floppy --fs-uuid --set=root F35E-F13C
        chainloader /EFI/BOOT/BOOTX64.EFI
    }
    ```
@@ -153,7 +180,7 @@ Two ways:
    POST): `efibootmgr -v` shows `neon` (Boot0005, on the USB card) and
    `Internal eMMC` (Boot0001), with `BootOrder` `0005,0001,0000,0003,0002`.
    With the USB card unplugged, the firmware falls through to `Internal
-   eMMC` and boots Flex with no menu.
+   eMMC` and boots FydeOS with no menu.
 
 ## Flex takes over the UEFI boot order on updates
 
@@ -206,13 +233,20 @@ Ways to live with it (none implemented yet):
 - Deleting `Boot0004` doesn't help: the next update recreates it.
   Neon's GRUB entry chainloads the ESP directly and doesn't need it.
 
-## Other ChromiumOS-based images: FydeOS
+After the FydeOS install, `Boot0004 "ChromeOS Flex"` was stale: it
+pointed at the old Flex ESP (PARTUUID `2877e60b…`, start sector
+`0x49000`), which no longer exists, so the firmware skipped it and fell
+through to neon. It was deleted 2026-09-27 (`efibootmgr -b 0004 -B`),
+which put `BootOrder` back to `0005,0001,0000,0003,0002`. Expect FydeOS
+to add its own entry, and move it first, after its first update.
 
-Checked 2026-09-27, by reading the image only (not installed):
+## FydeOS
+
+Checked 2026-09-27 by reading the image, then **installed the same day
+with `install-flex-emmc.sh` unchanged. It worked on the first try.**
 `FydeOS_for_PC_iris_v23.0-SP1-io.bin.zip` (board `amd64-fydeos_iris-io`,
 version `16700.56.23.51`), in `matt`'s `~/Downloads` (extracted copy in
-`~/fydeos-check`). **`install-flex-emmc.sh` should work with it
+`~/fydeos-check`).
-unchanged.**
 
 - **Same installer image layout:** ROOT-A is p3 (2.7GB), ROOT-B is a
   2MB placeholder, the ESP is p12. The same `chromeos-install` (Rust)
@@ -238,8 +272,8 @@ unchanged.**
   because Secure Boot is disabled on hp-chell (`mokutil --sb-state`).
   The image's ESP UUID is `F35E-F13C`.
 
-Caveats before trying it:
+Notes:
-- It replaces Flex (same eMMC, full wipe).
+- It replaced Flex (same eMMC, full wipe).
 - The script rewrites the UUID in the `40_custom` entry titled
   "ChromeOS Flex", so FydeOS boots under that title. Decided
   2026-09-27 to keep it, since FydeOS is effectively still ChromeOS.
@@ -255,4 +289,7 @@ Caveats before trying it:
   is normal for this class of eMMC). Booted as live/installer media, as
   explained above. The note at the time that Flex expands STATE on
   first boot was wrong.
-- **2026-09-27**: reinstalled properly with `install-flex-emmc.sh`.
+- **2026-09-27**: reinstalled Flex properly with `install-flex-emmc.sh`.
+  It worked and auto-updated, but took over the UEFI boot order.
+- **2026-09-27**: switched to FydeOS (`iris` build) with the same
+  script; deleted the stale Flex UEFI entry.

CLAUDE.md

@@ -16,7 +16,7 @@ This is a real **HP Chromebook 13 G1** ("chell" board), converted from ChromeOS
 - System: Manufacturer `Google`, Product Name `Chell`, Family `Google_Glados`, Serial `5CD732BLC9` — `Chell`/`Glados` is the Google Chrome OS board/reference codename for the HP Chromebook 13 G1.
 - Baseboard: Manufacturer `Google`, Product Name `Chell`, Serial `PFYTU018J90043`.
 - Implication: fanless Core m CPU, no way to add a fan — keep sustained-load expectations modest.
-- **Storage correction (2026-09-04)**: `sda` (117GB, where `/` lives) is actually an external USB/SD card (`lsblk` shows `TRAN=usb`) — the whole KDE neon install boots from that external card, not from anything internal. The real internal eMMC (`mmcblk0`, ~29GB) was blank until 2026-09-04, when ChromeOS Flex was installed onto it — see "Dual boot" section below. (Superseded the original note here, which incorrectly assumed `sda` was internal.)
+- **Storage correction (2026-09-04)**: `sda` (117GB, where `/` lives) is actually an external USB/SD card (`lsblk` shows `TRAN=usb`) — the whole KDE neon install boots from that external card, not from anything internal. The real internal eMMC (`mmcblk0`, ~29GB) was blank until 2026-09-04, when ChromeOS Flex was installed onto it — see "Dual boot" below. (Superseded the original note here, which incorrectly assumed `sda` was internal.)
 
 ## Kernel 7.x black-screen bug (diagnosed and fixed 2026-09-03)
 
@@ -117,20 +117,23 @@ flash itself, not a recurrence of the underlying i915 bug or a new
 problem. If it happens again right after a firmware update, try a forced
 power-off + power-on before assuming anything is actually broken.
 
-## Dual boot: KDE neon (USB) + ChromeOS Flex (internal eMMC)
+## Dual boot: KDE neon (USB) + ChromeOS (internal eMMC)
 
-ChromeOS Flex is installed on the internal eMMC (`/dev/mmcblk0`); neon
+**FydeOS** (ChromiumOS-based, `iris` build; replaced ChromeOS Flex on
+2026-09-27) is installed on the internal eMMC (`/dev/mmcblk0`); neon
 stays on the external `sda`. **Full details are in `CHROMEOS-FLEX.md`**,
 covering install/reinstall via `install-flex-emmc.sh`, why a raw `dd` of
 the recovery image boots as live media, `chromeos-install`-from-Linux
 gotchas, the partition layout, and boot selection.
 
 Quick reference:
-- Reinstall: `sudo ./install-flex-emmc.sh <flex .bin.zip or .bin>` (wipes
+- Reinstall: `sudo ./install-flex-emmc.sh <Flex or FydeOS .bin.zip or .bin>` (wipes
   the eMMC, masks every other disk, about 2.5 min, log in
   `/var/log/flex-install.log`).
-- Boot Flex from neon's GRUB menu with the "ChromeOS Flex (internal
+- Boot it from neon's GRUB menu with the "ChromeOS Flex (internal
   eMMC)" entry (in `/etc/grub.d/40_custom`; chainloads the ESP with FS
-  UUID `CBE4-703E`), or from the firmware picker (`Esc` at POST, then
+  UUID `F35E-F13C`; title kept from Flex), or from the firmware picker (`Esc` at POST, then
-  `Internal eMMC`). With the USB card unplugged, the firmware boots Flex
+  `Internal eMMC`). With the USB card unplugged, the firmware boots it
   directly.
+- ChromeOS updates re-add a UEFI entry and put it first in `BootOrder`;
+  see `CHROMEOS-FLEX.md`.