HL7802 update to firmware error "Failed to change baud rate"

I am trying to update the firmware of the HL7802 that we have mounted on our board. The current firmware is 4.3.9.0 and we want to upgrade to 4.6.8.0. The chip is powered and no communication with it is performed from our mcu. I am connected to the uart lines using a usb ttl-232r plugged in a windows machine.

I tried both the One-Click option and the sft Standlone and both aren’t working. Here is the debug output when I try to update with sft Standalone:

SFT v2.10.2101.0 Jan 29 2021 10:37:07
File to download: sysHeader_backup.bin.alt1250
File to download: u-boot.bin
File to download: sysHeader.bin.alt1250
File to download: partmap.bin
File to download: AppFW_flash.bin
File to download: ue_lte_2g.fw
File to download: ue_lte.fw2
File to download: sysHeader_modem.bin.alt1250

Using port COM5 at 921600 bps

Attempting communication at 115200 baud... success
Synchronizing with module...
AT port detected. Trying to synchronize with bootloader...
Synchronization success.
Flexible partition map detected
Flash mapping retrieved.
Using new flexible mapping.
Turbo mode available.
Downloading sysHeader_backup.bin.alt1250 segment 1
Starting download of 0x410 bytes
[>                                                 ] 0 % (0.00 KB/s)
Error while downloading sysHeader_backup.bin.alt1250 - aborting download
Failed to change baud rate
Hit ENTER to continue...

I don’t understand why the synchronization is successful but apparently it won’t change the baud rate.

How about using slower baud rate like 115200 ?