diff --git a/content/drone-stuff/ardupilot-setup-checklist.md b/content/drone-stuff/ardupilot-setup-checklist.md
index 14668bf..d930bdb 100644
--- a/content/drone-stuff/ardupilot-setup-checklist.md
+++ b/content/drone-stuff/ardupilot-setup-checklist.md
@@ -43,14 +43,14 @@ git submodule update --init --recursive
 
 git checkout Dockerfile
 echo "RUN pip install intelhex" >> Dockerfile
-echo 'ENV PATH="/home/ardupilot/.local/bin:/usr/lib/ccache:/ardupilot/Tools/autotest:/opt/'$(ls -1 /opt/ | grep gcc-arm-none-eabi)'/bin:${PATH}"' >> Dockerfile
+echo 'ENV PATH="/home/ardupilot/.local/bin:/usr/lib/ccache:/opt/gcc-arm-none-eabi-10-2020-q4-major/bin:/ardupilot/Tools/autotest:${PATH}"' >> Dockerfile
 cat Dockerfile
 
 docker build . -t ardupilot
 git checkout Dockerfile
 
-docker run --rm -it -v "$(pwd)":/ardupilot ardupilot:latest ./waf configure --board="$BOARD"
-docker run --rm -it -v "$(pwd)":/ardupilot ardupilot:latest ./waf build
+docker run --rm -it -v "$(pwd)":/ardupilot ardupilot ./waf configure --board="$BOARD"
+docker run --rm -it -v "$(pwd)":/ardupilot ardupilot ./waf build
 ```
 
 
diff --git a/content/software/_index.md b/content/software/_index.md
index 04b6e4f..a800f7a 100644
--- a/content/software/_index.md
+++ b/content/software/_index.md
@@ -9,3 +9,4 @@ insert_anchor_links = "right"
 Click on a link in the list below to go to that page:
 
 1. [Monero GUI syncing stuck with Ledger](../../software/monero-gui-syncing-stuck-with-ledger)
+1. [Test and format SD cards](../../software/test-and-format-sd-cards)
diff --git a/content/software/test-and-format-sd-cards.md b/content/software/test-and-format-sd-cards.md
new file mode 100644
index 0000000..38ed63f
--- /dev/null
+++ b/content/software/test-and-format-sd-cards.md
@@ -0,0 +1,31 @@
++++
+title = "Test and format SD cards"
+weight = 2
+sort_by = "weight"
+insert_anchor_links = "right"
++++
+I wrote a short bash script that tests SD cards with [F3](https://3ds.hacks.guide/f3-(linux).html) to see if they're fake, deletes everything on them, creates a new partition table and one exFAT partition on them.
+
+Here it is:
+
+```bash
+#!/usr/bin/env bash
+
+set -euox pipefail
+
+sudo umount --force "$1"1 || true
+sudo f3probe --destructive --time-ops "$1"
+sudo parted --script "$1" "mklabel msdos" "mkpart primary ext4 0% 100%"
+sleep 1
+sudo mkfs.exfat -n Stavros "$1"1
+eject "$1"
+```
+
+Save it as `formatsd.sh` and run it as `./formatsd.sh /dev/sdX`.
+
+* * *
+
+<p style="font-size:80%; font-style: italic">
+Last updated on August 18, 2021. For any questions/feedback,
+email me at <a href="mailto:hi@stavros.io">hi@stavros.io</a>.
+</p>