EFM8UB1 Datasheet, PDF (12/59 Pages) Silicon Laboratories – The EFM8UB1 highlighted features are listed below

EFM8UB1 Data Sheet
System Overview
3.10 Bootloader
All devices come pre-programmed with a USB bootloader. This bootloader resides in the code security page and last pages of code
flash; it can be erased if it is not needed.
The byte before the Lock Byte is the Bootloader Signature Byte. Setting this byte to a value of 0xA5 indicates the presence of the boot-
loader in the system. Any other value in this location indicates that the bootloader is not present in flash.
When a bootloader is present, the device will jump to the bootloader vector after any reset, allowing the bootloader to run. The boot-
loader then determines if the device should stay in bootload mode or jump to the reset vector located at 0x0000. When the bootloader
is not present, the device will jump to the reset vector of 0x0000 after any reset.
0xFFFF
0xFFC0
0xFFBF
0xFC00
0xFBFF
0xFBFE
Read-Only
Reserved
Lock Byte
Bootloader Signature Byte
0xFBC0
0xFBBF
0xF800
0xF7FF
0x4000
0x3FFF
Code Security Page
64 Bytes
Nonvolatile Data
Reserved
Bootloader Vector
16 KB Code
(32 x 512 Byte pages)
0x0000
Reset Vector
Figure 3.2. Flash Memory Map with Bootloader—16 KB Devices
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