From ddafd995c5eb78544ff731aaa1858bcb9f3f03f7 Mon Sep 17 00:00:00 2001
From: xRuffKez <p@schol.ing>
Date: Wed, 11 Nov 2026 19:32:53 +0100
Subject: [PATCH] Add Linux example for flashing with CH341 programmer

Added Linux setup instructions for Fedora 44 with CH341 programmer and flashrom usage.
---
 README.md | 90 ++++++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 89 insertions(+), 1 deletion(-)

diff --git a/README.md b/README.md
index 1e73941..2b3a35f 100644
--- a/README.md
+++ b/README.md
@@ -269,7 +269,7 @@ a command line.
 
 ### What you need
 
-- a Windows computer;
+- a Windows computer for NeoProgrammer, or the [tested Fedora setup below](#linux-example-fedora-44-and-ch341);
 - a CH341A/CH341B programmer verified for 3.3 V operation;
 - an SOIC-8 test clip and cable;
 - a multimeter;
@@ -357,6 +357,94 @@ Only after complete verification succeeds should you unplug the programmer,
 remove the clip, reconnect the camera's normal cable, and test it in the
 printer.
 
+### Linux example: Fedora 44 and CH341
+
+Windows and NeoProgrammer are not required for this route. A recovery completed
+on Fedora 44 with flashrom 1.6.0, cc2camera 0.9.0 and a CH341 programmer
+(`1a86:5512`). The camera was an `EF-S7-V1.0.30B` with an Ingenic T23 and a flash
+marked `25Q64DSIG`. Its measured JEDEC ID was **`5E 40 17`**, not the
+datasheet-derived `BA 32 17` initially discussed in
+[issue #28](https://github.com/OpenCentauri/cc2_camera_fix/issues/28). SFDP reported
+8 MiB. The camera's video feed worked again after flashing and reinstallation.
+
+The three original dumps were identical. The configuration area was 97.854%
+occupied, with 749 obsolete JFFS2 nodes. cc2camera accepted the dumps and built
+the recovery image in its default `serial-only` mode. The write passed full-chip
+verification and an independent complete readback. This result applies to the
+tested camera and firmware; it does not establish compatibility with other IDs
+or layouts.
+
+Follow the voltage and connection checks above. Install flashrom with
+`sudo dnf install flashrom` and cc2camera through the
+[Python installation instructions](docs/INSTALLATION.md). If using a virtual
+environment, use its command prefix in place of `cc2camera` below. Keep all
+commands in a new working directory and close other programmer applications.
+
+First probe without requesting a write:
+
+```sh
+flashrom -p ch341a_spi -VV
+```
+
+In the tested setup, the `Generic unknown SPI chip (RDID)` probe returned
+`id1 0x5e, id2 0x4017`. Although flashrom had no named profile for the part,
+SFDP detected an `SFDP-capable chip` with a capacity of `8192 kB`. Continue only
+if these values agree; do not force a similar chip definition.
+
+Read the complete flash three times without moving the clip:
+
+```sh
+flashrom -p ch341a_spi -c "SFDP-capable chip" -r cc2-camera-1.bin &&
+flashrom -p ch341a_spi -c "SFDP-capable chip" -r cc2-camera-2.bin &&
+flashrom -p ch341a_spi -c "SFDP-capable chip" -r cc2-camera-3.bin
+wc -c cc2-camera-1.bin cc2-camera-2.bin cc2-camera-3.bin
+cmp cc2-camera-1.bin cc2-camera-2.bin && cmp cc2-camera-1.bin cc2-camera-3.bin
+sha256sum cc2-camera-1.bin cc2-camera-2.bin cc2-camera-3.bin > original-SHA256SUMS.txt
+```
+
+Each file must contain exactly **8,388,608 bytes**. Both comparisons must succeed
+and all three hashes must match. Copy the dumps and checksum file to a separate
+drive, then run `sha256sum -c original-SHA256SUMS.txt` there. Every entry must
+report `OK` before continuing.
+
+Build the camera-specific image using all three reads:
+
+```sh
+cc2camera build-image cc2-camera-1.bin --confirm-read cc2-camera-2.bin --confirm-read cc2-camera-3.bin
+(cd cc2-camera-1-cc2-recovery && sha256sum -c SHA256SUMS.txt)
+```
+
+Stop if the build or checksum verification fails. The generated `FLASHING.txt`
+may contain a Bus Pirate/`COM11` template; do not use it unchanged with a CH341.
+Before writing, make another full read and require it to match the original:
+
+```sh
+flashrom -p ch341a_spi -c "SFDP-capable chip" -r cc2-camera-before-write.bin &&
+cmp cc2-camera-1.bin cc2-camera-before-write.bin
+```
+
+**The next command erases/programs flash.** Run it only after the comparison
+succeeds and the external original backup has been checked:
+
+```sh
+flashrom -p ch341a_spi -c "SFDP-capable chip" -w cc2-camera-1-cc2-recovery/cc2-camera-recovery.bin
+```
+
+flashrom erases/programs the required blocks and performs full-chip verification
+by default. Do not disable verification, use force options or change protection
+bits to bypass an error. After successful verification, read the whole chip
+again and compare it with the recovery image:
+
+```sh
+flashrom -p ch341a_spi -c "SFDP-capable chip" -r cc2-camera-readback.bin &&
+cmp cc2-camera-1-cc2-recovery/cc2-camera-recovery.bin cc2-camera-readback.bin
+sha256sum cc2-camera-1-cc2-recovery/cc2-camera-recovery.bin cc2-camera-readback.bin
+```
+
+The byte comparison must succeed and both hashes must match. Only then unplug
+the programmer, remove the clip and reconnect the camera to the powered-off
+printer. After reassembly, power on the printer and check the video feed.
+
 ## What the repair changes
 
 Affected cameras repeatedly rewrite the same configuration files during every