NRF52 OTAFIX Bootloader v2.1 Release!
Apologies for the bad release of v2.0, which broke DFU on iOS devices, this was due to an accidental reversion of the packet accumulator in main branch just before release.
Please see README.md for current recommended settings and troubleshooting.
⚠️ Important behaviour change
The default DFU mode is now OTA DFU.
When no valid application is present, the bootloader will not expose a UF2 drive or serial port unless explicitly requested via double-reset or the GPREGRET register.
🔄 Updating the bootloader
As always, using the UF2 file is the recommended way to update the bootloader, and if you are running MeshCore companion firmware then you must run a MeshCore flash erase afterwards in order to format the ExtraFS area.
Flashing the bootloader ZIP via adafruit-nrfutil will:
- Erase the existing application
- Leave the device in OTA DFU mode
This is expected behaviour.
Changes in OTAFIX 2.1
- Defaults to OTA DFU mode when no valid application is present, preventing devices from getting stuck in UF2 after failed OTA updates.
- High-MTU BLE support for faster DFU on clients that support large packets
(Android DFU app anddfu.py; iOS remains limited to 20-byte packets). - Lazy flash erase, erasing pages on demand during transfer to significantly reduce DFU initialisation time.
- Small-packet accumulation combines sub-64-byte packets into up to 240-byte writes, improving OTA performance from iOS and other small-packet DFU hosts.
- Fix: automatic reboot into application after OTA when connected to USB, eliminating the need for a manual reset.
- Unique BLE advertising names per board instead of AdaDFU:
- Heltec T114 →
T114_DFU - ProMicro NRF52840 →
PROM_DFU - T1000e →
T1KE_DFU - WioTracker L1 →
WTL1_DFU - RAK 4631** →
4631_DFU - RAK WisMesh Tag →
RTAG_DFU - XIAO NRF52 / BLE Sense →
XIAO_DFU
- Heltec T114 →
- Fix: un-revert the accidental small packet accumulator commit.