From 43af66c3886a10f6b73a830ddde6a9137a264659 Mon Sep 17 00:00:00 2001 From: Tim Crawford Date: Fri, 7 Aug 2020 11:31:32 -0600 Subject: [PATCH] docs: Extra info for flashing - Add note why first boot after flashing takes so long - Add note about power off when flashing EC - Add note on identifying the BIOS chip --- docs/flashing.md | 23 +++++++++++++++++++++-- 1 file changed, 21 insertions(+), 2 deletions(-) diff --git a/docs/flashing.md b/docs/flashing.md index 0b5a7a4..df66d38 100644 --- a/docs/flashing.md +++ b/docs/flashing.md @@ -2,18 +2,38 @@ **Flashing firmware manually is *not* recommended for the normal user!** +## Boot time + +The first boot after flashing will take a long time. This is due to coreboot +initializing RAM modules for the first time. Once memory training is complete, +coreboot will cache this information and subsequent boots will take +significantly less time. + +coreboot's `cbmem` tool can be used to verify this. The call to +`FspMemoryInit()` can report 20+ seconds on the first boot, and a few hundred +milliseconds on subsequent boots. + ## Internal programmer Use this method for flashing a system already running System76 Open Firmware. ``` -./scripts/flash.sh +./scripts/flash.sh [--without-ec] ``` +By default the script will attempt to flash the EC. If the EC is flashed, the +system will immediately power off. + ## External programmer Use one of these methods for first-time flashing or flashing a bricked system. +### Identifying the BIOS chip + +The packaging and protocol can be determined by `board_info.txt` in coreboot. +Laptops use a SOIC-8 package for the SPI flash ROM. Pin 1 is marked by a small +dot indent and a white paint mark. The silkscreen may also indicate pin 1. + ### CH341A USB programmer - slower, but easier to set up These can be purchased from many places for around 15 USD. Make sure that the @@ -72,4 +92,3 @@ cd firmware ``` SPIPI= ./scripts/spipi-flash.sh ``` -