disc] EMUI 9 C432 P20 Pro UK. Dload mode with service firmware. It does erase all data be warned. Link is here. Dload folder contains both the files for L09 and L29.
TPS Huawei Dload Flasher V1.1 - PiratesGSMKing
How To Flash Huawei (UPDATE.APP) Firmware Without SD Card - [romshillzz] - YouTube
Firmware Huawei without a computer (dload folder, .app flashing) on the example of Huawei Honor 4C - YouTube