I made a mistake and ran AT+KUSBCOMP=1 on an HL7812 module mounted on a custom PCB. Unfortunately, this specific board layout does not break out the physical USB interface to an external port, completely locking me out of standard AT command access over UART1.
Here is what I have tried so far:
- Flashing via UART0: I am still able to successfully flash the module firmware via the low-level UART0 bootloader interface.
- AT commands: Runtime AT commands do not work over UART0, so I cannot manually issue
AT+KUSBCOMP=0. - The Problem: The standard firmware update process over UART0 leaves the application NV parameter space intact. Therefore, when the modem reboots after the flash, it still prioritizes the missing USB stack, keeping UART1 dead.
Since I have functioning bootloader access via UART0, is there a specific command-line argument, parameter flag, or Python script modification I can use during the flash process to forcibly wipe/reset the NVM partition or restore factory defaults?
UART0 output:
NOR boot spl: Uncompressing u-boot image ... OK (141488 => 254824 55%)
Transferring control to u-boot ...
NOR boot spl: Uncompressing u-boot image ... OK (141488 => 254824 55%)
Transferring control to u-boot ...
U-Boot 2012.10 (Dec 15 2021 - 12:47:40) ALT1250_03_02_00_12_15041_UB
Board: ALT1250 Ver: 0.32-SB-E0 (PMP CPU Speed 120 MHz)
Platform id 9D9-989
DRAM: 3 MiB
Now running in RAM - U-Boot at: 902a4000
Boot mode 2
Flash Manufacturer/Device ID is: 0x20bb18
Enable QUAD mode
Flash: 16 MiB
*** Warning - Merge environment, using default environment
map import OK
USB CTRL has been successfully initialized!
In: usbtty
Out: usbtty
Err: usbtty
Configuring Flash Write Protection (offset 0x192e00)
new_ce_val = 0x3a0001f8
Rst info: shutdown : power on, no reset
Hit any key to stop autoboot: 0
Version: 2.0
Nothing to upgrade...
hbsb ok. 200 ms
## Starting
When I hit a button:
NOR boot spl: Uncompressing u-boot image ... OK (141488 => 254824 55%)
Transferring control to u-boot ...
NOR boot spl: Uncompressing u-boot image ... OK (141488 => 254824 55%)
Transferring control to u-boot ...
U-Boot 2012.10 (Dec 15 2021 - 12:47:40) ALT1250_03_02_00_12_15041_UB
Board: ALT1250 Ver: 0.32-SB-E0 (PMP CPU Speed 120 MHz)
Platform id 9D9-989
DRAM: 3 MiB
Now running in RAM - U-Boot at: 902a4000
Boot mode 2
Flash Manufacturer/Device ID is: 0x20bb18
Enable QUAD mode
Flash: 16 MiB
*** Warning - Merge environment, using default environment
map import OK
USB CTRL has been successfully initialized!
In: usbtty
Out: usbtty
Err: usbtty
Configuring Flash Write Protection (offset 0x192e00)
new_ce_val = 0x3a0001f8
Rst info: shutdown : power on, no reset
Hit any key to stop autoboot: 0
# <INTERRUPT>
#
Thanks in advance.