From 32eda52bb4e89c95dfd53a2d034808331f2ff910 Mon Sep 17 00:00:00 2001
From: Nick Klockenga <nick@klockenga.net>
Date: Wed, 2 Aug 2023 23:05:57 -0400
Subject: [PATCH] update manual install instructions for how to increase spidev
 buffer in cmdline.txt

---
 docs/manual_installation.md | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/docs/manual_installation.md b/docs/manual_installation.md
index 5b8ebadf..a8c63da5 100644
--- a/docs/manual_installation.md
+++ b/docs/manual_installation.md
@@ -215,6 +215,13 @@ workon seedsigner-env
 pwd
 ```
 
+### Optional: increase spidev buffer size
+This allows `ST7789.py` to update the LCD without performing multiple write operations because the default buffer size is 4096 bytes. The default can be changed via the  `/boot/cmdline.txt` file. You will need to add `spidev.bufsiz=131072` to the end of this single lined file command.
+
+Example `cmdline.txt` contents:
+```
+console=serial0,115200 console=tty1 root=PARTUUID=2fa4ba7e-02 rootfstype=ext4 elevator=deadline fsck.repair=yes rootwait modules-load=dwc2,g_ether spidev.bufsiz=131072
+```
 
 ### Configure `systemd` to run SeedSigner at boot: