[Motorola Droid RAZR] thegeologician:
update: still struggling, but giant leap further! Please read my tale...

...just in case anyone might find this useful, I'd like to give an update on my "patient":

I actually managed to flash ICS on there! Kind of.. What I did, was:

With the battery unplugged, I supplied external power to the phone, additional to the factory cable. The issue was that it would often flash small files, but for larger files would successfully "send" them, but in the "writing" phase the phone would just switch off. So, I supplied carefully monitored 3.7V to the contacts, which seemed to make a difference, but in the "writing" phase, Voltage dropped to below 3V where it would again switch off. Ok, you can charge a LiIon battery with max. 4.2V, and you should normally charge the battery before flashing, so I tried again while providing 4.2V. And - Success!! Voltage would drop to ~4V during "writing", but it stayed on, and allowed me to further test which Firmware the device would actually accept.

I do not believe that applying 5V from an USB cable directly to the (plugged-in) battery contacts, as mentioned in the forums somewhere, is very healthy for the battery. I reconnected the battery and tried charging it directly from the contacts, but I made sure the Voltage would always stay below 4.2V. Occasionally in my exploits, the charging circuitry would actually spring into action (confirmed by a drop and fluctuations in Voltage, and the faintest of noises from the phone itself), and I used that of course to squeeze some life back in, but most of the time it would not charge at all. I can not say what combination of flashing attempts, rebooting, un- and replugging the cable, switching and changing the charging current,... actually triggered the charging process occasionally, sorry. I could not reliably reproduce it.

In the process, I also tried the DroidRazrUtility 1.8, which interestingly flashed the AP fastboot to v 0A.74, but of course failed further on...

With the new AP fastboot, I thought maybe something more might now work, and at last I found it would now miraculously accept:

SPDREM_U_01.6.7.2-180_SPU-19-TA-11.6_SIGNEuropeAustraliaEMEA_USASPDRICSRTGB_HWp2b_Service1FF_fastboot.xml and

SPDREM_U_01.6.7.2-180_SPU-19-TA-11.6_SIGNEuropeAustraliaEMEA_USASPDRICSRTCEE_HWp2b_Service1FF_fastboot.xml

Fantastic!

First thing, before any actual booting, was to try if I could finally charge my battery again, and at last - yes!

At about 70%, I got adventurous, and unplugged the charger to put it in another power outlet. This made the phone actually boot up, but I thought that's not too bad now... But:

Now I have the following issue: After being freshly flashed (I tried several times now), it will charge as long as I don't actually switch it on, ONCE, but when it boots, after asking the setup questions and a little while on, it will switch off on its own, and then it's stuck in some variation of the bootloop (M dual core logo, pulsing M forever, OR rebooting ever and ever again at the pulsing M, OR just stuck at the M dual core). At least I now have a recovery menu. Erasing cache and data DON'T solve the issue (as proposed many times in the forums). I read a hint that it might be a kernel issue, or that it might be caused by a wrong radio.img (CDMA on a GSM phone). I checked and tested the latter by deactivating the radio in the extended settings, but it would still switch off after a short while (and it had defaulted to GSM, as it should).

So...am I stuck to wait for some new Firmware to come out, that might fix the issue? Or what should I try? Thanks in advance...