HTC One M8 - Stuck at Boot Screen after Stagefright OTA

Hi all,

This is my M8 - Stock, Rooted & S-OFF. It's an unlocked O2 one which I use on EE in the UK

M8_UL PVT SHIP S-OFF
CID-02___001
HBOOT-3.19.0.0000
RADIO-1.25.21331147A1.06G
OpenSDP-v48.2.2-00564-M8974_FO.1211
OS-4.20.206.1 <--- after the OTA, this now reads OS-4.20.206.2
eMMC-boot 2048MB

The Stagefright OTA for my M8 just downloaded, so I re-flashed recovery with one that I extracted from the last 5.0.1 OTA (it usually has the latest TWRP) & let it install the OTA. Everything went fine, it rebooted afterwards to recovery, then automatically rebooted again... & then it sticks at the boot screen after showing the O2 logo & chiming.

From the stuck boot screen, I can reboot it into the boot loader or recovery fine, but now when I boot it into recovery I get this:

Android system recovery <3e>
LRX22C release-keys

Volume up/down to move highlight;
enter button to select.

reboot system now
apply from sd card
wipe data/factory reset
wipe cache partition
reboot into bootloader
power down
view recovery logs
apply from phone storage
_____________________

E:missing bitmap oem_unlock_bg
(Code -1)
E:missing bitmap oem_unlock_bg_yes
(Code -1)
E:missing bitmap oem_unlock_bg_no
(Code -1)
Write host_mode success
handle_cota_install: No CW files. Skip cw installation.
What do you advise? :confused:

I haven't tried to factor reset it yet, but there is nothing on the phone that isn't backed up, so I can reset, re-flash or do anything required to get it back. As it's S-OFF, at a pinch I could change the SID & flash an entirely different ROM, although I have tended to stay Stock up until now...