Modem Firmware for GL-E750

I followed this tutorial for my Mudi E750v2 but stayed blocked at 99%:
Config:
Router Firmware 4.319
Modem Firmware flashed : EM060K: https://fw.gl-inet.com/download/EM060K-modem-firmware/EM060KGLAAR01A12M2GA.zip

...
[052.358]: upgrade progress 99% 118033380/118279820
[052.359]: send finished
[052.360]: <log value="Finished sector address 14592"/>
[052.362]: <response value="ACK" rawmode="false" />
[052.362]: <program PAGES_PER_BLOCK="64" SECTOR_SIZE_IN_BYTES="2048" filename="..\sbl1.mbn" num_partition_sectors="121"  physical_partition_number="0" start_sector="0" />
[052.364]: <log value="INSIDE HANDLE PROGRAM"/>
[052.365]: <log value="start_sector 0, last_sector_address 121"/>
[052.366]: <response value="ACK" rawmode="true" />
[052.366]: send ../sbl1.mbn, filesize=246440
.
gl_modem AT AT+QGMR

returns:

Modem is not exit.Please make sure bus.

I did a factory reset and retried. Same result.
Now my modem is not detected any more. I cannot restore the modem firmware at 100% so my router is unusable with 4G!

WHAT SHOULD I DO? Thanks for your help.