Install Grapheneos on Pixel 4a from Linux Mint

https://grapheneos.org/install/cli

sudo apt install android-sdk-platform-tools-common
echo 0 | sudo tee /sys/bus/usb/drivers_autoprobe
sudo apt install signify-openbsd
tar xvf sunfish-factory-2023080800.zip
cd sunfish-factory-2023080800
poweroff (hold vol - + power on) start on bootloader
fastboot flashing unlock
./flash-all.sh
fastboot too old; please download the latest version at https://developer.android.com/studio/releases/platform-tools.html
root@dell:/usr/lib/android-sdk/platform-tools# cp /home/vbits/Downloads/platform-tools/fastboot .
root@dell:/usr/lib/android-sdk/platform-tools# cp /home/vbits/Downloads/platform-tools/adb .
./flash-all.sh

Warning: skip copying bootloader_b image avb footer (bootloader_b partition size: 0, bootloader_b image size: 8574568).
Sending 'bootloader_b' (8373 KB) OKAY [ 0.400s]
Writing 'bootloader_b' (bootloader) Flashing Pack version s5-0.5-9825683
(bootloader) Flashing partition table for Lun = 0
(bootloader) Flashing partition table for Lun = 1
(bootloader) Flashing partition table for Lun = 2
(bootloader) Flashing partition table for Lun = 4
(bootloader) Flashing partition table for Lun = 5
(bootloader) Flashing partition xbl_b
(bootloader) Flashing partition xbl_config_b
(bootloader) Flashing partition aop_b
(bootloader) Flashing partition tz_b
(bootloader) Flashing partition hyp_b
(bootloader) Flashing partition abl_b
(bootloader) Flashing partition keymaster_b
(bootloader) Flashing partition cmnlib_b
(bootloader) Flashing partition cmnlib64_b
(bootloader) Flashing partition devcfg_b
(bootloader) Flashing partition qupfw_b
(bootloader) Flashing partition uefisecapp_b
(bootloader) Flashing partition logfs
OKAY [ 0.402s]
Finished. Total time: 1.351s
Setting current slot to 'b' OKAY [ 0.088s]
Finished. Total time: 0.222s
Rebooting into bootloader OKAY [ 0.057s]
Finished. Total time: 0.107s
Warning: skip copying bootloader_a image avb footer (bootloader_a partition size: 0, bootloader_a image size: 8574568).
Sending 'bootloader_a' (8373 KB) OKAY [ 0.390s]
Writing 'bootloader_a' (bootloader) Flashing Pack version s5-0.5-9825683
(bootloader) Flashing partition table for Lun = 0
(bootloader) Flashing partition table for Lun = 1
(bootloader) Flashing partition table for Lun = 2
(bootloader) Flashing partition table for Lun = 4
(bootloader) Flashing partition table for Lun = 5
(bootloader) Flashing partition xbl_a
(bootloader) Flashing partition xbl_config_a
(bootloader) Flashing partition aop_a
(bootloader) Flashing partition tz_a
(bootloader) Flashing partition hyp_a
(bootloader) Flashing partition abl_a
(bootloader) Flashing partition keymaster_a
(bootloader) Flashing partition cmnlib_a
(bootloader) Flashing partition cmnlib64_a
(bootloader) Flashing partition devcfg_a
(bootloader) Flashing partition qupfw_a
(bootloader) Flashing partition uefisecapp_a
(bootloader) Flashing partition logfs
OKAY [ 0.237s]
Finished. Total time: 1.134s
Setting current slot to 'a' OKAY [ 0.088s]
Finished. Total time: 0.218s
Rebooting into bootloader OKAY [ 0.056s]
Finished. Total time: 0.106s
Warning: skip copying radio_a image avb footer (radio_a partition size: 0, radio_a image size: 74125452).
Sending 'radio_a' (72388 KB) OKAY [ 2.550s]
Writing 'radio_a' (bootloader) Flashing Pack version SSD:g7150-00112-230505-B-10075601
(bootloader) Flashing partition modem_a
OKAY [ 0.357s]
Finished. Total time: 3.343s
Rebooting into bootloader OKAY [ 0.058s]
Finished. Total time: 0.109s
Erasing 'avb_custom_key' OKAY [ 0.217s]
Finished. Total time: 0.300s
Warning: skip copying avb_custom_key image avb footer (avb_custom_key partition size: 0, avb_custom_key image size: 1032).
Sending 'avb_custom_key' (1 KB) OKAY [ 0.140s]
Writing 'avb_custom_key' OKAY [ 0.230s]
Finished. Total time: 0.779s
Rebooting into bootloader OKAY [ 0.065s]
Finished. Total time: 0.115s
OKAY [ 0.024s]
Finished. Total time: 0.024s
Erasing 'apdp_a' OKAY [ 0.082s]
Finished. Total time: 0.211s
Erasing 'apdp_b' OKAY [ 0.083s]
Finished. Total time: 0.218s
Erasing 'msadp_a' OKAY [ 0.083s]
Finished. Total time: 0.215s
Erasing 'msadp_b' OKAY [ 0.083s]
Finished. Total time: 0.215s
Snapshot cancel OKAY [ 0.066s]
Finished. Total time: 0.066s
--------------------------------------------
Bootloader Version...: s5-0.5-9825683
Baseband Version.....: g7150-0xx2-2xxxx-B-1xxx601
Serial Number........: 0xxxx06
--------------------------------------------
extracting android-info.txt (0 MB) to RAM...
Checking 'product' OKAY [ 0.070s]
Checking 'version-bootloader' OKAY [ 0.070s]
Checking 'version-baseband' OKAY [ 0.070s]
Setting current slot to 'a' OKAY [ 0.084s]
extracting boot.img (64 MB) to disk... took 0.318s
archive does not contain 'init_boot.img'
extracting dtbo.img (8 MB) to disk... took 0.025s
archive does not contain 'dt.img'
archive does not contain 'pvmfw.img'
archive does not contain 'recovery.img'
extracting vbmeta.img (0 MB) to disk... took 0.000s
archive does not contain 'vbmeta_system.img'
archive does not contain 'vbmeta_vendor.img'
archive does not contain 'vendor_boot.img'
archive does not contain 'vendor_kernel_boot.img'
extracting super_empty.img (0 MB) to disk... took 0.000s
extracting product.img (480 MB) to disk... took 2.813s
[liblp] Partition product_a will resize from 0 bytes to 504029184 bytes
extracting system.img (1192 MB) to disk... took 8.269s
[liblp] Partition system_a will resize from 0 bytes to 1249964032 bytes
extracting system_ext.img (414 MB) to disk... took 2.573s
[liblp] Partition system_ext_a will resize from 0 bytes to 434724864 bytes
archive does not contain 'system_other.img'
extracting vendor.img (615 MB) to disk... took 3.923s
[liblp] Partition vendor_a will resize from 0 bytes to 645623808 bytes
archive does not contain 'vendor_other.img'
archive does not contain 'boot_other.img'
archive does not contain 'odm.img'
archive does not contain 'odm_dlkm.img'
archive does not contain 'system_dlkm.img'
archive does not contain 'system_other.img'
archive does not contain 'vendor_dlkm.img'
archive does not contain 'vendor_other.img'
extracting boot.img (64 MB) to disk... took 0.477s
archive does not contain 'boot.sig'
Sending 'boot_a' (65536 KB) OKAY [ 2.230s]
Writing 'boot_a' OKAY [ 0.226s]
extracting dtbo.img (8 MB) to disk... took 0.029s
archive does not contain 'dtbo.sig'
Sending 'dtbo_a' (8192 KB) OKAY [ 0.380s]
Writing 'dtbo_a' OKAY [ 0.095s]
extracting vbmeta.img (0 MB) to disk... took 0.000s
archive does not contain 'vbmeta.sig'
Sending 'vbmeta_a' (8 KB) OKAY [ 0.140s]
Writing 'vbmeta_a' OKAY [ 0.078s]
Sending sparse 'super' 1/11 (262140 KB) OKAY [ 9.015s]
Writing 'super' OKAY [ 0.911s]
Sending sparse 'super' 2/11 (230108 KB) OKAY [ 7.859s]
Writing 'super' OKAY [ 0.710s]
Sending sparse 'super' 3/11 (262140 KB) OKAY [ 8.950s]
Writing 'super' OKAY [ 0.800s]
Sending sparse 'super' 4/11 (262140 KB) OKAY [ 8.921s]
Writing 'super' OKAY [ 0.810s]
Sending sparse 'super' 5/11 (262140 KB) OKAY [ 8.950s]
Writing 'super' OKAY [ 0.780s]
Sending sparse 'super' 6/11 (262140 KB) OKAY [ 8.780s]
Writing 'super' OKAY [ 0.810s]
Sending sparse 'super' 7/11 (262140 KB) OKAY [ 9.051s]
Writing 'super' OKAY [ 0.790s]
Sending sparse 'super' 8/11 (262140 KB) OKAY [ 9.000s]
Writing 'super' OKAY [ 0.790s]
Sending sparse 'super' 9/11 (262140 KB) OKAY [ 9.051s]
Writing 'super' OKAY [ 0.800s]
Sending sparse 'super' 10/11 (262140 KB) OKAY [ 9.190s]
Writing 'super' OKAY [ 0.810s]
Sending sparse 'super' 11/11 (178576 KB) OKAY [ 6.090s]
Writing 'super' OKAY [ 0.570s]
Finished. Total time: 127.453s
Rebooting into bootloader OKAY [ 0.012s]
Finished. Total time: 0.064s

In the bootloader interface, set it to locked:

fastboot flashing lock

Disabling OEM unlocking