Red screen updating CX CAS to 4.5

[johnmark]

I installed nloader to install CAS on my CX (non-CAS) a few years ago, and updated to 4.0.3.93 too, with ndless.
Today I followed this guide to try to update my calculator to 4.5.4.48: viewtopic.php?f=57&t=22530 and viewtopic.php?f=57&t=18920#updatecx
It updated (or installed controlx) on the diags partition, then I deleted the 4.0 OS by the manuf mode and installed the 4.5 CAS OS. However, on rebooting, it goes to that "Your calculator has been modified to enable CAS functionality" screen and after booting the OS, it goes to a red screen. I tried to erase the OS again and try to flash 4.0.3.93 back but it won't let me downgrade the OS, as the minimum version is now 4.5.
I tried following other guides, however Ctrl+Menu+Minus doesn't seem to do anything on boot...
Any way to unbrick my calculator?

[SlyVTT]

Don't know if it could change something, but which "Minus" key did you use ?
There are 2 "Minus" keys on the CX/CX-II :
- the one close to PLUS and labeled "-"
- the one between the dot and the ENTER Key and labeled "(-)"
If you only tried one, maybe should you try the other one.

[critor]

You are mentioning both nLoader and nBoot+ControlX.

They target 2 different and totally incompatible TI-Nspire CX hardware revisions. If you followed our guides, it's explained at the beginning.
There is no way they're both going to work on the same calculator.

If I understand correctly, you've got :

• nLoader installed and working on your calculator which must be a CR4+ calculator (assembled after 2015)
• ControlX installed in the Diags partition but unable to be launched since it isn't compatible with CR4+ calculators

esc

menu

-

won't work anymore since you made your Diags partition unbootable (by overwriting it with the incompatible ControlX image).

doc

enter

ee

is your last chance. If it triggers something, then try to delete the OS and install any working OS. Then it'll be possible to install Ndless and fix things.

If

doc

enter

ee

doesn't work, I fear there is no software/free way to repair your calculator.

You'll need an USB/TTL interface in order to reflash a bootable image in your partitions.

[johnmark]

You are mentioning both nLoader and nBoot+ControlX.

They target 2 different and totally incompatible TI-Nspire CX hardware revisions. If you followed our guides, it's explained at the beginning.
There is no way they're both going to work on the same calculator.

If I understand correctly, you've got :

• nLoader installed and working on your calculator which must be a CR4+ calculator (assembled after 2015)
• ControlX installed in the Diags partition but unable to be launched since it isn't compatible with CR4+ calculators

esc

menu

-

won't work anymore since you made your Diags partition unbootable (by overwriting it with the incompatible ControlX image).

doc

enter

ee

is your last chance. If it triggers something, then try to delete the OS and install any working OS. Then it'll be possible to install Ndless and fix things.

If

doc

enter

ee

doesn't work, I fear there is no software/free way to repair your calculator.

You'll need an USB/TTL interface in order to reflash a bootable image in your partitions.

DOC+EE+Enter works and I can erase the OS. However, I can only upgrade my OS to further version, and those versions are incompatible with nLoader, so it results in the red screen. if I send any older version, or CX version, it rejects.
My calculator is old, so the boot1 version is 3.0.0.99 , today I upgraded controlx to version 5, and every boot I have that message that the calculator was modified. However, if I press those button combination (the minus sign being the one to reduce brightness), the message still appears. I press those button combination on resetting the calculator, and by pulling out the battery and turning it on with the combination, however, the "your calculator has been modified" screen always appears.

[critor]

Thanks for clarifying.

If you can't install an Ndless-able OS and if your Diags partition isn't bootable anymore, then I'm sorry but same reply : there is no software way to restore your calculator.

The nLoader installation guide makes you install a bootable Boot2 image in the Diags partition in order to be able to recover from such situations, since nLoader (unlike ControlX) doesn't include any maintenance menu.
But you overwrote it.

[johnmark]

Thanks for clarifying.

If you can't install an Ndless-able OS and if your Diags partition isn't bootable anymore, then I'm sorry but same reply : there is no software way to restore your calculator.

The nLoader installation guide makes you install a bootable Boot2 image in the Diags partition in order to be able to recover from such situations, since nLoader (unlike ControlX) doesn't include any maintenance menu.
But you overwrote it.

I have an arduino, is there any way to recover it in that way?
Thanks.

[critor]

Sorry, I don't have any experience with the Arduino.

You need an USB/TTL interface, it's usually quite cheap :
https://www.amazon.com/s?k=usb+ttl

Then connect it like this :


Setup the computer software to :

Baud rate : 115200.
Data : 8 bit.
Parity : none.
Stop : 1 bit.
Flow control : none

Hold

doc

enter

2

while turning on your calculator, to reflash the Boot2 partition.

And then send a clean bootable image (no nLoader), like this one for example :
archives_voir.php?id=481757

Good luck, feel free to ask again for help if needed.

[johnmark]

Sorry, I don't have any experience with the Arduino.

You need an USB/TTL interface, it's usually quite cheap :
https://www.amazon.com/s?k=usb+ttl

Then connect it like this :


Setup the computer software to :

Baud rate : 115200.
Data : 8 bit.
Parity : none.
Stop : 1 bit.
Flow control : none

Hold

doc

enter

2

while turning on your calculator, to reflash the Boot2 partition.

And then send a clean bootable image (no nLoader), like this one for example :
archives_voir.php?id=481757

Good luck, feel free to ask again for help if needed.

Are the pins on the CX 2015 the same as on that calculator (TX, RX and GND).
Aditionally, what's the best way to connect or to solder them?
Finally, what's the preferred way to flash the boot (program/software), when connected to the usb adapter (I have a FT232RL)

[johnmark]

My TI nspire model is also the TI-Nspire CX / Firebird variant P:
P P 0614 NSC SM MB 4412 NSC CELL (Non)CAS KB 4410 Firebird Color BTB 2440
according to here: https://hackspire.org/index.php/Hardware
I disassembled my calculator to get a chance to solder the pins and I came across the dock connector as Firebird_Color_BTB_2440.
Are the TX, RX and GND pins the same, and can I flash it the same way as in the instructions?

[critor]

Same pins as the ones on the picture :


You only need 1 GND pin, just choose what's easier for you.

Beware, pins numbering is reversed on hackspire, compared to what you can read on your calculator PCB.