As far as I know, including those mentioned, there are a total of 6 (2 are combined):
- DAS U-Boot
- TTXS (Smartcard Reader)
- USB PD Controller
- Firmware Jail (also includes Redpine RS9116 firmware)
- BM818-x1
The first four on this list can be performed sequentially directly during and after reflashing the Librem 5. The last two are performed on the Librem 5 itself.