From 42d28305caa5cb38578d7fa9ac66e6d77c111c5d Mon Sep 17 00:00:00 2001 From: Jorijn van der Graaf Date: Sun, 9 Aug 2026 01:10:16 +0200 Subject: [PATCH] README: the modemst wipe is 'fastboot flash boot', precisely Isolated by experiment (2026-08-09, journal/modem): flash boot alone zeroes modem NV; erase dtbo and idle fastboot visits are safe; on-device boot-deploy (incl. apk kernel upgrades) never trips it. Likely ABL anti-tamper on boot-image overwrite under an unlocked bootloader. Co-Authored-By: Claude Fable 5 --- README.md | 23 ++++++++++++++--------- 1 file changed, 14 insertions(+), 9 deletions(-) diff --git a/README.md b/README.md index 51e628d..7ffc587 100644 --- a/README.md +++ b/README.md @@ -41,15 +41,20 @@ Default login: `user` / `147147` (same as official postmarketOS images — change it). **Never re-lock the bootloader** with a custom image installed. > [!WARNING] -> **Back up your modem's NV partitions before flashing.** Flash sessions have -> been observed to zero `modemst1`/`modemst2` on this device, after which the -> modem reports no IMEI and neither SIM slot answers (`no-atr-received`) — -> including the eSIM. The profiles themselves are safe in the eUICC, but only -> a restore of working `modemst` images brings access back; stock Android -> re-provisions them on boot, postmarketOS cannot. Before your first flash: -> `dd` both partitions to files from a rooted stock system (or from a running -> pmOS: `/dev/disk/by-partlabel/modemst1` and `modemst2`) and keep them -> forever. Restore with `dd` in the other direction, then reboot. +> **`fastboot flash boot` zeroes the modem's NV storage on this device** +> (`modemst1`/`modemst2`) — verified by isolation experiment; `fastboot erase +> dtbo` and idle fastboot sessions are safe. Afterwards the modem reports no +> IMEI and neither SIM slot answers (`no-atr-received`), eSIM included. The +> eSIM profiles themselves are safe in the eUICC; stock Android silently +> re-provisions the NV from `fsg` on boot, postmarketOS cannot. +> +> Practical rules: +> - **Back up first**: from a running postmarketOS (or rooted stock), `dd` +> `/dev/disk/by-partlabel/modemst1` and `modemst2` to files, keep forever. +> - **After install, restore them**: `dd` back and reboot — cellular returns. +> - **Never update the kernel via fastboot** — installed systems update boot +> through on-device `boot-deploy` (which apk kernel upgrades run +> automatically), never tripping the wipe. ## VoLTE configuration