Сони Ериксон решиха да се опитат да поправят грешките които имаха в софтуера на популярния си модел K750i.
Повече информация: 
R1N035 – Released by SEUS Asia Pacific & the US on 12/9/05
- Video bitrate improvements over R1L
- Improvements to photo quality
- Bluetooth stability fixes
- Signal strength indicator shows extra bar / improved reception
- JBenchmark 3D LQ – approx 204
- JBenchmark 3D HQ – approx 123
- Software versions: LCD 0
- Camera 4.5
- ITP CXC 125 932 R1E
Ето и информация за предишните версии:
R1A044 – First release (K750 only)
- JBenchmark 1 – approx 3894
- JBenchmark 2 – approx 334
- JBenchmark 3D LQ – approx 131
- JBenchmark 3D HQ – approx 89
- Software versions: LCD 0
- Camera 3.8
- ITP CXC 125 932 R1B
R1C004 – Vodafone specific (K750 only) – Released around 3/6/05 – No reported changes from R1A044
- As is the case with the K700, Vodaphone’s R1C004 supports DRMed MP3s only.
- Software versions: LCD 0
- Camera 3.8
- ITP CXC 125 932 R1B
R1J002 – Released on SEUS 13/6/05 – Standby crash fixed / improved.
- Increased call and Media Player volume.
- Games menu operates much more smoothly.
- Smoother video playback
- General UI performance improvements
- Improvements and bug fixes to Bluetooth headset support.
- The auto focus beep sound has been changed.
- Saving a photo to the Memory Stick is now quicker.
- New MP3 folder on Memory stick
- Fixed the month names in the calendar for various european languages.
- Camera sounds are muted when in silent mode in some firmware locales (EU_1 , but not EU_3).
- Minimised Media Player icon changed.
- SMS ‘to’ text now black (previously white).
- A „Fully Charged“ message is now displayed on screen when the phone has finished charging.
- * PROBLEM: GPRS comms has been broken on many O2 phones and some phones from other service providers.
- * PROBLEM: Video recording quality (bitrate) has been reduced.
- JBenchmark 1 – approx 3908
- JBenchmark 2 – approx 344
- JBenchmark 3D LQ – approx 205
- JBenchmark 3D HQ – approx 114
- Software versions: LCD 0
- Camera 4.4
- ITP CXC 125 932 R1B
R1K001 – W800 brown (pre-release) firmware
R1L002 – Released by DaVinci on 22/6/05 – Released on SEUS 30/6/05
- Fixes the O2 GPRS issue introduced in R1J
- Video recording quality as R1J (i.e. inferior to firmwares previous to R1J)
- JBenchmark 1: 3880
- JBenchmark 2: 335
- JBenchmark 3D LQ – approx 201
- JBenchmark 3D HQ – approx 121
- Software versions: LCD 0
- Camera 4.4
- ITP CXC 125 932 R1B
