How do I regain access to either the filesystem or terminal on a raspberry pi that has all networking services disabled and no terminal?

Question

Due to some unfortunate configuration settings, I kludged my raspberry pi into not having a terminal (it normally boots into an app, which still works fine) nor having network access.

I can no longer access the filesystem nor the terminal so I can't actually fix the problem.

Essentially, I was trying to enable wifi and in doing so, disabled network services. When I restarted my Pi, my ethernet cable no longer provided a connection, and that was the only way I was able to remote into the pi to develop on it.

I've tried resetting the cmdline.txt and config.txt files to enable simple access to the terminal, but nothing I'm trying works. What should I do?

Here is my cmdline.txt

console=tty1 root=PARTUUID=41b52e18-02 rootfstype=ext4 elevator=deadline fsck.repair=yes rootwait video=HDMI-A-1:1080x1920M@60,rotate=90

and config.txt

# uncomment if you get no picture on HDMI for a default "safe" mode
#hdmi_safe=1

# uncomment this if your display has a black border of unused pixels visible
# and your display can output without overscan
#disable_overscan=1

# uncomment the following to adjust overscan. Use positive numbers if console
# goes off screen, and negative if there is too much border
#overscan_left=16
#overscan_right=16
#overscan_top=16
#overscan_bottom=16

# uncomment to force a console size. By default it will be display's size minus
# overscan.
#framebuffer_width=1280
#framebuffer_height=720

# uncomment if hdmi display is not detected and composite is being output
#hdmi_force_hotplug=1

# uncomment to force a specific HDMI mode (this will force VGA)
#hdmi_group=1
#hdmi_mode=1

# uncomment to force a HDMI mode rather than DVI. This can make audio work in
# DMT (computer monitor) modes
#hdmi_drive=2

# uncomment to increase signal to HDMI, if you have interference, blanking, or
# no display
#config_hdmi_boost=4

# uncomment for composite PAL
#sdtv_mode=2

#uncomment to overclock the arm. 700 MHz is the default.
#arm_freq=800

# Uncomment some or all of these to enable the optional hardware interfaces
dtparam=i2c_arm=on
#dtparam=i2s=on
dtparam=spi=off

# Uncomment this to enable infrared communication.
#dtoverlay=gpio-ir,gpio_pin=17
#dtoverlay=gpio-ir-tx,gpio_pin=18

# Additional overlays and parameters are documented /boot/overlays/README

# Enable audio (loads snd_bcm2835)
dtparam=audio=on

[pi4]
# Enable DRM VC4 V3D driver on top of the dispmanx display stack
dtoverlay=vc4-fkms-v3d
max_framebuffers=2

[all]
dtoverlay=vc4-fkms-v3d

# Waveshare Edits #
max_framebuffer_height=1920
max_usb_current=1
hdmi_group=2
hdmi_mode=87
hdmi_timings=1080 0 112 16 160 1920 0 4 10 10 0 0 0 60 0 140000000 3

scaling_kernel=8
display_hdmi_rotate=3
gpu_mem=512

enable_uart=1
display_rotate=3

Answer 1

Your SD card (or whatever media you boot from) has two partitions - one is ext4 filesystem (/); the other is FAT32 filesystem (/boot). You may remove the SD card, then mount and edit anything in /boot on virtually any computer (Windows, Mac, Linux, Unix, etc). The ext4 partition can typically only be mounted on a Linux system.

Your config.txt and cmdline.txt files are located in the FAT32 partition (/boot/config.txt) - therefore you may edit it, and correct your errors on virtually any computer.

Make sure you use an editor that does not use CR-LF to end a line (i.e. no Windows Notepad)

Answer 2

Try adding rw init=/bin/bash to the cmdline.txt: that should unconditionally boot your system into a root terminal, which allows you to edit the configuration files you have messed up (re-enabling the network services).