Unable to remove WP from Craasneto Acer Chromebook 314-4H-C739 even with SuzyQcable

Support General Device Support
1

System Details

  • Device: [ChromeOS board name]
  • OS: [ChromeOS, Linux, Windows]
  • Firmware Type: [Stock, RW_LEGACY, UEFI Full ROM]
  • Firmware Version: [As reported by the script]
  • Internal storage type: [SATA, NVMe, eMMC, UFS] (if applicable)

Summary of the Issue

[Briefly describe what is happening]

Steps to Reproduce

Expected Behavior

* Have Done the PP process
* Battery Disconnected
* Verfied that the SuzyQcable is functional by running ls /dev/ttyUSB*, they all show up.

Have tried running the following commands
echo “wp false” > /dev/ttyUSB0
echo “wp false atboot” > /dev/ttyUSB0
Run echo “ccd reset factory” > /dev/ttyUSB0

Even with root they don’t seem to change the WP status, still locked when running gsctool -a -I and crossystem wpsw_cur is still at 1

Have also tried connecting the USBA to another laptop and running the commands from it to the chromebook, no effect, WP still locked.

Does this laptop have a jumper on the motherboard that is missed in the documentation?.

GSC Debug Board v4.1.0 dec 19 2023

Thanks in advance for any help.

2

why would you disconnect the battery? that’s NOT part of the process, and causes the GSC to re-lock

3

Excuse my confusion, I now redid it with the battery connected and it flashed successfully, thank you for your work and have a nice day :slight_smile:

Thread closed.

4

I also had this problem. But even with battery connected, I installed popOS and the next day I could not turn on the laptop. I was then somehow able to boot it using the recovery procedure using power and 2x refresh icon, Release power button and repeat.
But it only give me now 15 minutes of runtime.

I also made the mistake of going back to stock ROM and now I am stuck in chromos for 15 minutes as the process to repeat takes more time than 15 minutes to enable developer mode and gsctool enabling.

Any idea on how to solve this issue?

5

crossystem wpsw_curwas 0 before flashing the full UEFI ROM

6
  • power off / disconnect battery
  • using another device, connect SuzyQ
  • open terminal to ttyUSB0
  • run ‘ccd open’ then ‘ccd reset factory’
  • disconnect SuzyQ / reconnect battery
1 Like
7

That’s what the problem is: ccd is now locked somehow and flags are reset to defaults

> ccd

ccd

State: Locked

Password: none

Flags: 0x00000000

Capabilities: 0x0000000000000000

UartGscRxAPTx Y 0=Default (Always)

UartGscTxAPRx Y 0=Default (Always)

UartGscRxECTx Y 0=Default (Always)

UartGscTxECRx - 0=Default (IfOpened)

UartGscRxFpmcuTx Y 0=Default (Always)

UartGscTxFpmcuRx - 0=Default (IfOpened)

FlashAP - 0=Default (IfOpened)

FlashEC - 0=Default (IfOpened)

OverrideWP - 0=Default (IfOpened)

RebootECAP - 0=Default (IfOpened)

GscFullConsole - 0=Default (IfOpened)

UnlockNoReboot Y 0=Default (Always)

UnlockNoShortPP Y 0=Default (Always)

OpenNoTPMWipe - 0=Default (IfOpened)

OpenNoLongPP - 0=Default (IfOpened)

BatteryBypassPP Y 0=Default (Always)

I2C - 0=Default (IfOpened)

FlashRead Y 0=Default (Always)

OpenNoDevMode - 0=Default (IfOpened)

OpenFromUSB - 0=Default (IfOpened)

OverrideBatt - 0=Default (IfOpened)

AllowUnverifiedRo - 0=Default (Never)

Capabilities are default.

FactInit: N

TPM:

Use ‘ccd help’ to print subcommands

how to proceed?

8

you should be able to open the CCD with the battery disconnected using another machine as per my instructions above

9

Port /dev/ttyUSB0, 07:48:33 [U]

Press CTRL-A Z for help on special keys

*** Ti50 RESET ***
[ 0.045] RBOX: WP true
[ 0.045] RBOX: assert EC_RST_L
[ 0.048] cryptolib v1 at 0x100c00
[ 0.051]
[ 0.057] RBOX: assert EC_RST_L
[ 0.057] AP SPI WP register SR-1 is not correct! Got 00, expected to matcc
[ 0.065] AP RO: NOT OK
[ 0.068] AP RO verifications took 10 ms.
[ 0.078] 9 files found across 4 pages.
[ 0.079] 4375 bytes of data.
[ 0.082] 0 invalid and 6 free pages.
[ 0.086] 0 erases since bo
*** DATA LOST ***

ccd open
ccd open
[ 11.356] RBOX: WP true
Blocked: run from AP in devmode, remove batt, or short chassis_open
Command ‘ccd’ failed: Access Denied

On battery disconnected, I am getting this. Not able to open ccd in any way. Also, the chromebook can’t start without the battery and just the red LED keeps blinking when trying the power plus refresh option to disable RO verification. Can only do it once the battery is connected. I don’t see any jumper points as well to disable HW WP

10

Also, somehow I am now getting 4 ttyUSB
ls /dev/ttyUSB*
/dev/ttyUSB0 /dev/ttyUSB1 /dev/ttyUSB2 /dev/ttyUSB3

11

Got it working now.
I think I ran the firmware-util script as root user.
What fixed it for me was to enable developer mode again (with battery connected- otherwise not booting) after PP done as quickly as possible and just after that, sending
ccd set AllowUnverifiedRo Always

This then removed the 15 minutes timer from Ti50

Just enough time :sweat_smile:

Thanks alot for the help.